Zhi-Kuang Tan

• PhD in Physics
• Professor (Associate) at National University of Singapore

The recently emerging two‐dimensional (2D) hybrid lead‐halide perovskites are mostly templated by “inert” organic cations, limiting their light emission solely from the inorganic components. Using “optically active” organic cations can grant access to the coupling between the two luminescent components, potentially leading to new excitation and emi...

The recently emerging two‐dimensional (2D) hybrid lead‐halide perovskites are mostly templated by “inert” organic cations, limiting their light emission solely from the inorganic components. Using “optically active” organic cations can grant access to the coupling between two luminescent components, potentially leading to new excitation and emissio...

Tuning quantum emission to a specific wavelength at room temperature holds significant promise for enhancing secure quantum communication, particularly by aligning with the Fraunhofer lines in the solar spectrum. The integration of quantum emitters with phase‐change materials enables emission wavelength modulation, especially when strong field enha...

Controlling and channeling light emissions from unpolarized quantum dots into specific directions with chiral polarization remains a key challenge in modern photonics. Stacked metasurface designs offer a potential compact solution for chirality and directionality engineering. However, experimental observations of directional chiral radiation from r...

Perovskite nanocrystals (PNCs) are promising luminescent materials for electronic color displays due to their high luminescence efficiency, widely‐tunable emission wavelengths, and narrow emission linewidth. Their application in emerging display technologies necessitates precise micron‐scale patterning while maintaining good optical performance. Al...

Metal halide perovskite quantum dots (PQDs) have emerged as promising materials due to their exceptional photoluminescence (PL) properties. A wide range of applications could benefit from adjustable luminescence properties, while preserving the physical and chemical properties of the PQDs. Therefore, post‐synthesis engineering has gained attention...

Metal halide perovskite quantum dots (PQDs) have emerged as promising materials due to their exceptional photoluminescence (PL) properties. A wide range of applications could benefit from adjustable luminescence properties, while preserving the physical and chemical properties of the PQDs. Therefore, post-synthesis engineering has gained attention...

Ternary CuInS2 quantum dots (QDs) with photoluminescence tunable from the visible to near-infrared (NIR) region are promising light-emitters for consumer electronics due to the absence of toxic elements such as Pb, Cd or As. Despite the compelling performance of visible emitting CuInS2 QDs, reports on NIR emission remain limited with modest efficie...

Short-wave infrared (SWIR) light emission is important for a diverse range of modern applications, such as eye-safe depth sensing, light detection and ranging (LiDAR), facial recognition, eye tracking, optical communication and health monitoring technologies. However, there is a very limited number of known semiconductors that could emit efficientl...

Spectral tuning in lead halide perovskite semiconductors is generally achieved by mixing halide compositions or by quantum confinement effects. However, mixed-halide perovskites exhibit undesirable phase separation during optical and electrical...

The advent of lead halide perovskite nanocrystals (NCs), which are easily synthesized, ultralow-cost materials and have an impeccable luminous efficiency, has drastically changed the future perspective of semiconductor quantum dot devices. Although the band gap energy of lead perovskite NCs can be tuned by the halide composition, the instability pr...

Traditional colloidal quantum dots rely on larger‐bandgap semiconductor shells for the localization of excitons in their emissive core. Unshelled quantum dots are typically weakly luminescent due to severe quenching by deep electronic traps. Lead halide perovskite nanocrystals deviate from this convention and require only common monofunctional alip...

Fluorescent dyes with a high photoluminescence quantum yield (PLQY) and photostability are favored in bioimaging as they offer better imaging signals at lower dye loading, circumventing issues of cytotoxicity and biological pathway interference. Quantum dots (QDs) are efficient emitters with narrow spectral line‐widths, but often employ toxic heavy...

Across the different classes of sodium‐ion battery cathodes, Prussian Blue holds the greatest promise because of its high working potentials, abundance, low‐toxicity and ease of synthesis. However, its performance as a sodium‐ion battery cathode has generally been limited to less than 120 mAh g−1, which is inferior compared to commercial lithium‐ba...

Mobile and wearable devices are increasingly reliant on near-infrared (NIR) covert illumination for facial recognition, eye-tracking or motion and depth sensing functions. However, these small devices offer limited spatial real estate that is typically already occupied by their full-area electronic color displays. Here, we report a transparent pero...

Fluorescence imaging using charge‐coupled device cameras has become the prevailing method for the investigation of cancer drug efficacy in in vivo preclinical trials involving animal models. The lack of imaging depth, however, limits the use of fluorescence techniques to small murine models, and compels large animal models to rely on more‐costly ma...

The performance of perovskite light-emitting diodes (PeLEDs) has progressed rapidly in recent years, with electroluminescence efficiency now reaching 20%1,2,3,4,5,6,7,8,9,10,11,12. However, devices, so far, have featured small areas and usually show notable variation in device-to-device performance. Here, we show that the origin of suboptimal devic...

Size control is critical in the synthesis of quantum-confined semiconductor nanocrystals, otherwise known as quantum dots. The achievement of size-uniformity and narrow spectral line-width in quantum dots conventionally relies on a very precise kinetic control of the reactions, where reaction time plays a significant role in defining the final crys...

Beyond the stability improvement for PSCs, elegant approaches to further improve their energy conversion efficiency are also desired. Bifacial photovoltaic is anticipated to be a highly interesting alternative to improve the output power of semitransparent PSCs. However, this approach has so far attracted little attention in the field of PSCs. In t...

The ability for a magnetic field to penetrate biological tissues without attenuation has led to significant interest in the use of magnetic nanoparticles for biomedical applications. In particular, active research is ongoing in the areas of magnetically guided drug delivery and magnetic hyperthermia treatment. However, the difficulties in tracing t...

Near‐infrared (NIR) lighting plays an increasingly important role in new facial recognition technologies and eye‐tracking devices, where covert and nonvisible illumination is needed. In particular, mobile or wearable gadgets that employ these technologies require electronic lighting components with ultrathin and flexible form factors that are curre...

Lead halide perovskite possesses a semiconductor bandgap that is readily tunable by a variation in its halide composition. Here, a photo‐activated halide exchange process between perovskite nanocrystals and molecular haloalkanes is reported, which enables the perovskite luminescence to be controllably shifted across the entire visible spectrum. Mec...

Infrared-emitting materials with large Stokes shift and minimal reabsorption are technologically-important for luminescent solar concentrators and for bio-imaging applications. Here, we describe the synthesis of new InAs-In(Zn)P-ZnSe-ZnS qua-ternary giant-shell quantum dots that possess efficient photoluminescence (PL) in the near-infrared. We empl...

Lead halide perovskite semiconductors first gained prominence in photovoltaic technology, where they demonstrated impressive photon-to-electron conversion efficiencies in solution-processed devices. The benefits of perovskites are, however, more vividly-expressed in light-emitting applications. This new class of halide semiconductors displays inten...

The use of photon energy to promote chemical transformations offers versatile control of reaction kinetics and progress. Over the past decade, many photoactive transition-metal complexes and organic chromophores were developed to catalyze chemical transformations, enabling a myriad of reactions and compounds that were previously inaccessible via tr...

Metal halide perovskites have demonstrated rich photophysics and remarkable potential in photovoltaic and electroluminescent devices. However, the photoactivity of perovskite semiconductors in chemical processes remains relatively unexplored. Here, a general approach toward the synthesis of luminescent perovskite–polymer nanocomposites is reported,...

Infrared emitters are reasonably rare in solution-processed materials. Recently, research into hybrid organo-lead halide perovskite, originally popular in photovoltaics, has gained traction in light-emitting diodes (LED) due to their low-cost solution processing and good performance. The lead-based electroluminescent materials show strong colorful...

This work was supported by the EPSRC [Grant numbers EP/M005143/1, EP/J017361/1 and EP/G037221/1]. G.L. thanks Gates Cambridge Trust for funding. F.W.R.R. is grateful for financial support from CNPq [Grant number 246050/2012-8]. N.J.L.K.D. thanks the Cambridge Commonwealth European and International Trust, Cambridge Australian Scholarships and Mr Ch...

Electroluminescence in light-emitting devices relies on the encounter and radiative recombination of electrons and holes in the emissive layer. In organometal halide perovskite light-emitting diodes, poor film formation creates electrical shunting paths, where injected charge carriers bypass the perovskite emitter, leading to a loss in electrolumin...

In recent years, organometal halide perovskite materials have attracted significant research interest in the field of optoelectronics. Here, we introduce a simple and low-temperature route for the formation of self-assembled perovskite nanocrystals in a solid organic matrix. We demonstrate that the size and photoluminescence peak of the perovskite...

High-performance perovskite light-emitting diodes are achieved by an interfacial engineering approach, leading to the most efficient near-infrared devices produced using solution-processed emitters and efficient green devices at high brightness conditions. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. The line for this article was changed on February 19, 2015, after original online publication. Fluorene-free perovskite light-emitting diodes (LEDs)...

Solid-state light-emitting devices based on direct-bandgap semiconductors have, over the past two decades, been utilized as energy-efficient sources of lighting. However, fabrication of these devices typically relies on expensive high-temperature and high-vacuum processes, rendering them uneconomical for use in large-area displays. Here, we report...

Injection and extraction of charges through ohmic contacts are required for efficient operation of semiconductor devices. Treatment using polar non-solvents switches polar anode surfaces, including PEDOT:PSS and ITO, from barrier-limited hole injection and extraction to ohmic behaviour. This is caused by an in-situ modification of the anode surface...

The structure evolution of all-polymer solar cells based on the blends of poly(3-hexylthiophene) (P3HT) and poly[(9,9-dioctyluorene)-2,7-diyl-alt-(4,7-bis(3-hexylthien-5-yl)-2,1,3-benzothiadiazole)-2′,2′′-diyl] (F8TBT) was investigated. The P3HT/F8TBT system exhibits crystallization-driven structure formation similar to the P3HT/phenyl-C61-butyrica...

An energy cascading structure is designed in a polymer photovoltaic device to suppress recombination and improve quantum yields. By the insertion of a thin polymer interlayer with intermediate energy levels, electrons and holes can effectively shuttle away from each other while being spatially separated from recombination. An increase in open-circu...

A cross-linking moiety having a structure represented by formula (I) or (II): N3-ArF-W (I) (N3-ArF-W)n-L (II) wherein ArF comprises a fluorinated phenyl group having at least one non-fluorine substituent (R) that is bulkier than fluorine and which is located at the meta position relative to the N3 group; W comprises an electron-withdrawing group...