Zhigang Shuai

• PhD, Fudan University
• Chair at Tsinghua University

Electronic excited state in molecular aggregate or exciton states continue to attract great attention due to the increasing demands for applications of molecular optoelectronics and sensing technology. The working principle behind the application is closely related to the excited state structure and dynamic processes in molecular aggregate. In our...

As one of the most important concepts in organic chemistry, aromaticity has attracted considerable attention from both theoretical and experimental chemists. Limited by the traditional rules (Hückel’s rules and Baird’s rules), species can only achieve aromaticity in a single state (S0 or T1) in most cases. In 2018, our group first reported 16 elect...

Quantum computational chemistry holds great promise for simulating molecular systems more efficiently than classical methods by leveraging quantum bits to represent molecular wavefunctions. However, current implementations face significant limitations in accuracy due to hardware noise and algorithmic constraints. To overcome these challenges, we in...

The accurate prediction of lattice thermal conductivity in organometallic thermoelectric materials is crucial for advancing energy conversion technologies. Methods based on molecular dynamics simulations can solve this problem well, but...

In microcavity, strong coupling between light and molecules leads to the formation of hybrid excitations, i. e., the polaritons, or exciton‐polaritons. Such coupling may alter the energy landscape of the system and the optical properties of the material, making it an effective approach for controlling the light emission from molecular materials. Ho...

Tree tensor network states (TTNS) decompose the system wavefunction to the product of low-rank tensors based on the tree topology, serving as the foundation of the multi-layer multi-configuration time-dependent Hartree method. In this work, we present an algorithm that automatically constructs the optimal and exact tree tensor network operators (TT...

Tree tensor network states (TTNS) decompose the system wavefunction to the product of low-rank tensors based on the tree topology, serving as the foundation of the multi-layer multi-configuration time-dependent Hartree (ML-MCTDH) method. In this work, we present an algorithm that automatically constructs the optimal and exact tree tensor network op...

Organic molecular materials are potential high-performance thermoelectric materials. Theoretical understanding of thermoelectric conversion in organic materials is essential for rational molecular design for efficient energy conversion materials. In organic materials, nonlocal electron-phonon coupling plays a vital role in charge transport and lead...

Deep-red/near-infrared fluorescence is highly suitable for bioimaging owing to its ability to deeply penetrate tissues, organs, and live animals. However, developing organic fluorophores with high deep-red/near-infrared fluorescence quantum yield (ΦFL) and fluorescent brightness remain a significant challenge owing to the energy gap law. Herein, we...

Room temperature phosphorescence (RTP) from pure organic materials, whether in crystalline or film phases, has recently attracted considerable attention. Experimental evidence increasingly suggests that RTP originates from isomeric dopants (impurity) rather than pure compounds. The underlying mechanism and molecular design principles have remained...

Quantum transport in molecular junctions has attracted great attention. The charge motion in a molecular junction can cause geometric deformation, leading to strong electron phonon coupling, which was often overlooked. We have formulated a nearly exact method to assess the time-dependent current and occupation number in the molecular junction model...

The widely known “Energy Gap Law” (EGL) predicts a monotonically exponential increase in the non-radiative decay rate (knr) as the energy gap narrows, which hinders the development of near-infrared (NIR) emissive molecular materials. Recently, several experiments proposed that the exciton delocalization in molecular aggregates could counteract EGL...

TenCirChem is an open-source Python library for simulating variational quantum algorithms for quantum computational chemistry. TenCirChem shows high-performance in the simulation of unitary coupled-cluster circuits, using compact representations of quantum states and excitation operators. Additionally, TenCirChem supports noisy circuit simulation a...

Exciton coherence length (ECL) characterizes the spatial extent of coherently delocalized excited states of molecular aggregates. Constructive/destructive superpositions of coherent molecular dipoles lead to superradiance/subradiance, where the radiative rate is enhanced/suppressed compared to that of a single molecule. Longer ECLs correspond to fa...

Digital quantum simulation of electron-phonon systems requires truncating infinite phonon levels into N basis states and then encoding them with qubit computational basis. Unary encoding and binary encoding are the two most representative encoding schemes, which demand O(N) and O(logN) qubits as well as O(N) and O(NlogN) quantum gates, respectively...

TenCirChem is an open-source Python library for simulating variational quantum algorithms for quantum computational chemistry. Its easy-to-use high-level interface enables users to optimize molecular energies or study quantum dynamics in only a few lines of code, while still allowing for a high degree of flexibility and customizability. By making u...

Room temperature phosphorescence (RTP) from pure organic materials in crystalline or film phase has attracted great attentions recently. More and more experimental evidences pointed out that RTP is originated from isomeric dopant, instead of pure compound. The underlying mechanism and molecular design principle are unclear till now. Herein, using q...

Digital quantum simulation of electron-phonon systems requires truncating infinite phonon levels into $N$ basis states and then encoding them with qubit computational basis. Unary encoding and the more compact binary/Gray encoding are the two most representative encoding schemes, which demand $\mathcal{O}(N)$ and $\mathcal{O}(\log{N})$ qubits as we...

The widely known ``Energy Gap Law'' (EGL) predicts a monotonically exponential increase in the non-radiative decay rate (knr) as the energy gap narrows, which hinders the development of near-infrared (NIR) emissive molecular materials. Recently, several experiments proposed that the exciton delocalization in molecular aggregates could counteract EG...

Integration of luminescence and carrier transport is of prime interest for optoelectronics, but full with challenges in organic semiconductors. Previously, it has been demonstrated that intermolecular charge transfer (ICT) in the herringbone H‐aggregate can lend oscillator strength to the lowest‐lying dark state if electron transfer (te) and hole t...

Abstract We computationally investigated the molecular aggregation effects on the excited state deactivation processes by considering both the direct vibrational relaxation and the S0/S1 surface crossing, that is, the minimum energy conical intersection (MECI). Taking classical AIEgens bis(piperidyl)anthracenes (BPAs) isomers and the substituted si...

Organic/polymeric materials are of emerging importance for thermoelectric conversion. The soft nature of these materials implies strong electron-phonon coupling, often leading to carrier localization. This poses great challenges for the conventional Boltzmann transport description based on relaxation time approximation and band structure calculatio...

Achieving high exciton utilization is a long-cherished goal in the development of organic light-emitting diode materials. Herein, a three-step mechanism is proposed to achieve 200% exciton utilization: (i) hot triplet exciton (T2) conversion to singlet S1; (ii) singlet fission from S1 into two T1; (iii) and then a Dexter energy transfer to phosphor...

Two‐coordinate Cu (I) complexes have attracted great interest recently because of the rich photophysical property in solid state, including the aggregation‐induced thermal activated delayed fluorescence. Here, we summarize our theoretical investigations on the excited state structure and decay dynamics for the two‐coordinate Cu (I) complexes in sol...

Exciton coherence length (ECL) is an essential concept to characterize the nature of exciton in molecular aggregates for photosynthesis, organic photovoltaics, and light-emitting diodes. ECL has been defined in a number of ways through the variance or purity of the electronic reduced density matrix. However, we find that these definitions fail to p...

The study of aggregation-induced emission luminogens (AIEgens) shows promising perspectives explored in lighting, optical sensors, and biological therapies. Due to their unique feature of intense emissions in aggregated solid states, it smoothly circumvents the weaknesses in fluorescent dyes, which include aggregation-caused quenching of emission a...

Quantum computing has recently exhibited great potential in predicting chemical properties for various applications in drug discovery, material design, and catalyst optimization. Progress has been made in simulating small molecules, such as LiH and hydrogen chains of up to 12 qubits, by using quantum algorithms such as variational quantum eigensolv...

Using a photonic quantum computer for boson sampling has demonstrated a tremendous advantage over classical supercomputers. It is highly desirable to develop boson sampling algorithms for realistic scientific problems. In this work, we propose a hybrid quantum-classical sampling (HQCS) algorithm to calculate the optical spectrum for complex molecul...

Organic/polymeric materials are of emerging importance for thermoelectric conversion. The soft nature of these materials implies strong electron-phonon coupling, often leading to carrier localization. This poses great challenges for the conventional Boltzmann transport description based on relaxation time approximation and band structure calculatio...

Molecular skeletons with active photoluminescence emission in both dispersed and aggregated states are important for diverse applications. As planarization of molecular configuration in the excited state has been shown to be a critical precondition for efficient emission, developing luminogens with pristine planar geometry seem to be the most strai...

Density matrix renormalization group (DMRG) and its time-dependent variants have found widespread applications in quantum chemistry, including ab initio electronic structure of complex bio-molecules, spectroscopy for molecular aggregates, and charge transport in bulk organic semiconductors. The underlying wavefunction ansatz for DMRG, matrix produc...

We derive a stochastic hierarchy of matrix product states (HOMPS) for non-Markovian dynamics in an open quantum system at finite temperature, which is numerically exact and efficient. HOMPS is obtained from the recently developed stochastic hierarchy of pure states (HOPS) by expressing HOPS in terms of formal creation and annihilation operators. Th...

Using a photonic quantum computer for boson sampling has been demonstrated a tremendous advantage over classical supercomputers. It is highly desirable to develop boson sampling algorithms for realistic scientific problems. In this work, we propose a hybrid quantum-classical sampling (HQCS) algorithm to calculate the optical spectrum for complex mo...

The simulations of spectroscopy and quantum dynamics are of vital importance to the understanding of the electronic processes in complex systems, including the radiative/radiationless electronic relaxation relevant for optical emission, charge/energy transfer in molecular aggregates related to carrier mobility in organic materials, as well as photo...

Deep understanding of the inherent luminescence mechanism via theoretical framework computational tools sheds light on the rapid development of aggregation-induced emission (AIE) materials and applications. In this chapter, we comprehensively introduce the computational modeling of AIE luminogens via four steps. First, we comparatively investigate...

Detection of organic amines is a pivotal issue in chemistry. Here we present the synthesis of a novel fluorescence probe with “turn-on” greenish emissive (486 nm) response towards series of...

Novel functional AIEgen based on three compact bound aryl skeletons is designed and synthesized. This tri‐aryl type luminogen (TA‐Catechol) embedded with catechol moiety responds rapidly to series of boronic acids. Real‐time visual and quantitative dual‐mode detection method is established for the first time with modest precision and low detection...

Organic phosphorescence, originating from triplet excitons, has potential for the development of new generation of organic optoelectronic materials. Herein, two heavy-atom-free room-temperature phosphorescent (RTP) electron acceptors with inherent long lifetime triplet exctions are first reported. These two 3D-fully conjugated rigid perylene imide...

The current research of mechanochromic molecules focused on different molecular skeletons and the types of functional groups, where the design ideas were limited. We have synthesized a group of cyano-modified TPE derivatives (TPECN) with different substitution sites, showing typical aggregation induced emission (AIE) effect. We found that meta-subs...

We propose a method to calculate the spectral functions of many-body systems by Chebyshev expansion in the framework of matrix product states coupled with canonical orthogonalization (coCheMPS). The canonical orthogonalization can improve the accuracy and efficiency significantly because the orthogonalized Chebyshev vectors can provide an ideal bas...

We propose a method to calculate the spectral functions of many-body systems by Chebyshev expansion in the framework of matrix product states coupled with canonical orthogonalization (coCheMPS). The canonical orthogonalization can improve the accuracy and efficiency significantly because the orthogonalized Chebyshev vectors can provide an ideal bas...

Quantum computing has recently exhibited great potentials in predicting chemical properties for various applications in drug discovery, material design, and catalyst optimization. Progress has been made in simulating small molecules, such as LiH and hydrogen chains of up to 12 qubits, by using quantum algorithms such as variational quantum eigensol...

We derive a hierarchy of matrix product states (HOMPS) method which is numerically exact and efficient for general non-Markovian dynamics in open quantum system. This HOMPS is trying to attack the exponential wall issue in the recently developed hierarchy of pure states (HOPS) scheme with two steps: a. finding an effective time-dependent Schr\"odin...

We propose a method to calculate the spectral functions of strongly correlated systems by Chebyshev expansion in the framework of matrix product states coupled with canonical orthogonalization (coCheMPS). The canonical orthogonalization can improve the accuracy and efficiency significantly because the orthogonalized Chebyshev vectors can provide an...

We propose a method to calculate the spectral functions of strongly correlated systems by Chebyshev expansion in the framework of matrix product states coupled with canonical orthogonalization (coCheMPS). The canonical orthogonalization can improve the accuracy and efficiency significantly because the orthogonalized Chebyshev vectors can provide an...

The first example of luminescent monosubstituted polyacetylenes (mono‐PAs) is presented, based on a contracted cis‐cisoid polyene backbone. It has an excellent circularly polarized luminescence (CPL) performance with a high dissymmetric factor (up to the order of 10⁻¹). The luminescence stems from the helical cis‐cisoid PA backbone, which is tightl...

Pursuing purely organic materials with high-efficiency near-infrared (NIR) emissions is fundamentally limited by the large non-radiative decay rates (k nr) governed by the energy gap law. To date, reported endeavors to decelerate k nr are mainly focused on reducing the electron-vibration coupling with the electronic nonadiabatic coupling assumed as...

We propose a method for calculating the nonradiative decay rates for polyatomic molecules including anharmonic effects of the potential energy surface (PES) in the Franck-Condon region. The method combines the n-mode representation method to construct the ab initio PES and the nearly exact time-dependent density matrix renormalization group method...

We propose a method for calculating the nonradiative decay rates for polyatomic molecules including anharmonic effects of the potential energy surface (PES) in the Franck-Condon region. The method combines the n-mode representation method to construct the ab initio PES and the nearly exact time-dependent density matrix renormalization group method...

Inspired by the formulation of quantum-electrodynamical time-dependent density functional theory (QED-TDDFT) by Rubio and co-workers [Flick et al., ACS Photonics 6, 2757-2778 (2019)], we propose an implementation that uses dimensionless amplitudes for describing the photonic contributions to QED-TDDFT electron–photon eigenstates. This leads to a He...

The development of high mobility organic laser semiconductors with strong emission is of great scientific and technical importance, but challenging. Herein, we present a high mobility organic laser semiconductor, 2,7‐diphenyl‐9H‐fluorene (LD‐1) showing unique crystallization‐enhanced emission guided by elaborately modulating its crystal growth proc...

The conjugated polymer monosubstituted polyacetylenes (mono-PAs) have been generally considered to be non-emissive. Herein we report the first example of luminescent mono-PAs based on contracted cis-cisoid polyene backbone, displaying an excellent circularly polarized luminescence (CPL) performance with a high dissymmetric factor (up to the order o...

A high mobility organic lasing semiconductor of 2,7-diphenyl-9H-fluorene (LD-1) with crystallization-enhanced emission is demonstrated. The light emitting transistor based on an individual LD-1 nanowire crystal gives typical electrically induced emission. This work provides a new concept for developing superior organic lasering semiconductors to ad...

The nonlocal electron-phonon couplings in organic semiconductors responsible for the fluctuation of intermolecular transfer integrals has been the center of interest recently. Several irreconcilable scenarios coexist for the description of the nonlocal electron-phonon coupling, such as phonon-assisted transport, transient localization, and band-lik...

Organic photodetectors displaying efficient photoelectric response in the near-infrared are typically based on narrow bandgap active materials. Unfortunately, the latter require complex molecular design to ensure sufficient light absorption in the near-infrared region. Here, we show a method combining an unconventional device architecture and ad-ho...

In this work, we propose a new method to calculate molecular nonradiative electronic relaxation rates based on the numerically exact time-dependent density matrix renormalization group theory. This method could go beyond the existing frameworks under the harmonic approximation (HA) of the potential energy surface (PES) so that the anharmonic effect...

Deep understanding of the inherent luminescence mechanism is essential for the development of aggregation‐induced emission (AIE) materials and applications. We first note that the intermolecular excitonic coupling is much weaker in strength than the intramolecular electron‐vibration coupling for a majority of newly termed AIEgens, which leads to th...

p> We have proposed a facile strategy to achieve large triple gap by manipulating the aromaticity and the transition properties of the low-lying excited states, then theoretically designed and experimentally verified a series of donor-bridge-acceptor based on partially conjugated five-membered rings with high aromaticity in T₁ state to m...

Superior organic light-emitting transistors (OLETs) materials require two conventionally exclusive properties: strong luminescence and high charge mobilities. We propose a three-state model through localized diabatization to quantitative analyze excited state structures for various herringbone (HB) H-aggregates and demonstrate that for some investi...

Aggregation-induced emission (AIE) fluorophores exhibit strong fluorescence in an aggregated state but emit no or weak fluorescence in dilute solutions. This emerging class of AIE optical materials comprise a variety of functionalities. Here an AIE luminescence core, 1-hydroquinol-1,2,2-triphenylethene (HQTPE), has been designed and synthesized. Th...

div>In this work, we propose a new method to calculate the molecular nonradiative electronic relaxation rates based on the numerically exact time-dependent density matrix renormalization group theory (TD-DMRG). This method could go beyond the existing frameworks under the harmonic approximation (HA) of the potential energy surface (PES) so that the...

p>The pursuing of purely organic materials with high-efficiency near-infrared (NIR) emissions is fundamentally limited by the large non-radiative decay rates ( k _nr) governed by the energy gap law. Here, we demonstrated a feasible and innovative strategy by employing intermolecular charge-transfer (CT) aggregates (CTA) to realize high-ef...

The two-coordinate carbene-metal-amide complexes have attracted a great deal of attention due to their remarkable thermally activated delayed fluorescence (TADF) properties, giving them promise in organic light-emitting diode application. To reveal the inherent mechanism, we take CAAC-Cu(I)-Cz and CAAC-Au(I)-Cz as examples to investigate the photop...

Recently, Wang and co-workers carried out frontier molecule orbital engineering in the design of m-Cz-BNCz, a thermally activated delayed fluorescence (TADF) molecule that emits pure green light at an external quantum efficiency of 27%. To further understand the underlying molecular design principles, we employed four advanced electronic structure...

The thermally activated delayed fluorescence (TADF) phenomenon has attracted increasing attention because it can harvest 100% of the electro-pumped carriers to form singlet bound excited state for fluorescence. It is generally believed that the small energy gap between S1 and T1 (ΔEST) is essential for TADF to facilitate the reverse intersystem cro...

The role of dynamic and static disorders has been widely discussed for carrier transport in organic semiconductors. In this work we apply a multiscale approach by combining the molecular dynamics simulations, quantum mechanics calculations and kinetic Monte-Carlo simulations to study the influence of dynamic and static disorders on the hole mobilit...

It is a big challenge to achieve high-performance organic semiconductor materials integrating both high luminescence efficiency and carrier mobility, because they are commonly regarded as a pair of contradiction. Here, combining a tight-binding model and density functional theory/time-dependent density functional theory, we propose a theoretical pr...

ConspectusRoom-temperature phosphorescence (RTP) with a long afterglow from purely organic molecular aggregates has recently attracted many investigations because traditionally only inorganic and transition-metal complexes can emit phosphorescence at room temperature. Purely organic molecules can exhibit phosphorescence only at cryogenic temperatur...

The role of nonlocal electron-phonon couplings (EPC) in organic semiconductors has the been center of interest recently. Several irreconcilable scenarios coexist for the description of the nonlocal EPC, such as phonon-assisted (PA) transport, transient localization (TL), and band-like (BL) transport. In this Letter, we present a nearly exact numeri...

Integration of ferroelectricity into van der Waals heterostructures offers additional opportunities to control over the properties and functionalities of heterostructures by switching the direction of the polarization via an external electric field. To discover potential ferroelectric monolayers that exhibit out-of-plane electric polarizations, we...

Slot‐die coating is generally regarded as the most effective large‐scale methodology for the fabrication of organic solar cells (OSCs). However, the corresponding device performance significantly lags behind spin‐coated devices. Herein, the active layer morphology, flexible substrate properties, and the processing temperature are optimized synergis...

Thermally activated delayed‐fluorescent (TADF) materials are anticipated to overcome triplet‐related losses towards electrically driven organic lasers. Thus far, contributions from triplets to lasing have not yet been experimentally demonstrated owing to the limited knowledge about the excited‐state processes. Herein, we experimentally achieve reve...

Analysis of subcellular organelles (e.g. cytoplasm membrane and mitochondria) during cellular processes can provide particularly useful information for our understanding of cell chemistry and biology. For this purpose, fluorescent probes capable of dynamically imaging multiple organelles in a simultaneous and selective manner are highly demanded, y...

A new aggregation-induced emission (AIE) luminescence core, 1-hydroquinol-1,2,2-triphenylethene (HQTPE), has been designed and synthesized for the first time. This AIE core is amazingly simple but is fundamentally important to chemistry because of its intrinsic redox and pH activities. The incorporation of hydroquinone (HQ) moiety into a common AIE...

Electrically pumped organic lasing is one of the most challenging issues in organic optoelectronics. We present a systematic theoretical investigation to screen out electrical pumping lasing molecules over a wide range of organic materials. With the electronic structure information obtained from time-dependent density functional theory, we calculat...

Marcus theory has been successfully applied to molecular design for organic semiconductors with the aid of quantum chemistry calculations for the molecular parameters: the intermolecular electronic coupling V and the intramolecular charge reorganization energy λ. The assumption behind this is the localized nature of the electronic state for represe...

Constructing matrix product operators (MPOs) is at the core of the modern density matrix renormalization group (DMRG) and its time dependent formulation. For the DMRG to be conveniently used in different problems described by different Hamiltonians, in this work, we propose a new generic algorithm to construct the MPO of an arbitrary operator with...

It is generally perceived that fast reverse intersystem crossing rate of T1→S1 (krisc) is crucial for efficient organic thermally activated delayed fluorescence (TADF) emitters. We demonstrate here that for transition metal complexes, the non-radiative decay rate of T1→S0 (knrT) is even more important. We calculated the interconversion rates among...

Accurate theoretical description of the electronic structure for boron-dipyrromethene (BODIPY) molecules has been a challenging topic over the years, let alone the prediction of fluorescence quantum efficiency. In this letter, we show that the electronic structures of BODIPYs can be accurately evaluated via the spin-flip time-dependent density func...

Reverse intersystem crossing‐boosted lasing was experimentally demonstrated in self‐assembled microspheres with uniformly dispersed organic thermally activated delayed‐fluorescence molecules. The lasing intensity increases with increasing temperature due to the involvement of regenerated singlets in population inversion, which provides a way to ove...

High-mobility and strong luminescent materials are essential as an important component of organic photodiodes, having received extensive attention in the field of organic optoelectronics. Beyond the conventional chemical synthesis of new molecules, pressure technology, as a flexible and efficient method, can tune the electronic and optical properti...

div>As is well known, the thermally activated delayed fluorescence (TADF) is always generated from charge-transfer (CT) excited states in electron-donor (D) – electron-acceptor (A) systems. Here, a novel design strategy is proposed for realizing TADF from a locally excited (LE) state through controlling the intersystem crossing (ISC) and reverse in...

Recent events including the publication of troubling remarks in Angewandte Chemie have made clear that many in the scientific community and broader society continue to face systemic racism and discrimination in their daily personal and professional lives. As these events unfold, we must take personal responsibility and commit to supporting all memb...

With recent progress in photothermal materials, organic small molecules featured with flexibility, diverse structures, and tunable properties exhibit unique advantages but have been rarely applied in solar‐driven water evaporation owing to limited sunlight absorption resulting in low solar–thermal conversion. Herein, a stable croconium derivative,...

Aggregation‐induced/‐enhanced emission (AIE/AEE) has aroused broad interest. The mechanism behind is understood as the aggregation restriction of the nonradiative decay from electronically excited state to the ground state, either through interconversion or through conical intersection, leaving the dipole‐allowed radiative decay channel relatively...

A large number of non-adiabatic dynamical studies have been applied to reveal the nature of carrier transport in organic semiconductors with different approximations. We present here a “nearly exact” graphical process unit (GPU) based finite temperature TD-DMRG method to evaluate the carrier mobility in organic semiconductors as described by electr...