Dendritic CsSnI for Efficient and Flexible Near-Infrared Perovskite Light-Emitting Diodes.

All-inorganic and lead-free CsSnI is emerging as one of the most promising candidates for near-infrared perovskite light-emitting diodes (NIR Pero-LEDs), which find practical applications including facial recognition, biomedical apparatus, night vision camera, and Light Fidelity. However, in the CsSnI -based Pero-LEDs, the holes injection is significantly higher than that of electrons, resulting in unbalanced charge injection, undesired exciton dissipation, and poor device performance. Herein, it is proposed to manage charge injection and recombination behavior by tuning the interface area of perovskite and charge-transporter.

Composition engineering to obtain efficient hybrid perovskite light-emitting diodes.

Metal halide perovskites have received considerable attention in the field of electroluminescence, and the external quantum efficiency of perovskite light-emitting diodes has exceeded 20%. CHNHPbBr has been intensely investigated as an emitting layer in perovskite light-emitting diodes. However, perovskite films comprising CHNHPbBr often exhibit low surface coverage and poor crystallinity, leading to high current leakage, severe nonradiative recombination, and limited device performance.

Ultrathin PEDOT:PSS Enables Colorful and Efficient Perovskite Light-Emitting Diodes.

Recently, metal halide perovskite light-emitting diodes (Pero-LEDs) have achieved significant improvement in device performance, especially for external quantum efficiency (EQE). And EQE is mostly determined by internal quantum efficiency of the emitting material, charge injection balancing factor (η), and light extraction efficiency (LEE) of the device. Herein, an ultrathin poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (UT-PEDOT:PSS) hole transporter layer is prepared by a water stripping method, and the UT-PEDOT:PSS can enhance η and LEE simultaneously in Pero-LEDs, mostly due to the improved carrier mobility, more matched energy level alignment, and reduced photon loss.

Efficient and Stable Low-Bandgap Perovskite Solar Cells Enabled by a CsPbBr-Cluster Assisted Bottom-up Crystallization Approach.

Recently, low-bandgap formamidinium lead iodide FAPbI-based perovskites are of particular interest for high-performance perovskite solar cells (PSCs) due to their broad spectral response and high photocurrent output. However, to inhibit the spontaneous α-to-δ phase transition, 15-17% (molar ratio) of bromide and cesium or methylammonium incorporated into the FAPbI are indispensable to achieve efficient PSCs. In return, the high bromide content will increase bandgap and narrow the spectral response region.

Perovskite light-emitting diodes with external quantum efficiency exceeding 20 per cent.

Metal halide perovskite materials are an emerging class of solution-processable semiconductors with considerable potential for use in optoelectronic devices. For example, light-emitting diodes (LEDs) based on these materials could see application in flat-panel displays and solid-state lighting, owing to their potential to be made at low cost via facile solution processing, and could provide tunable colours and narrow emission line widths at high photoluminescence quantum yields. However, the highest reported external quantum efficiencies of green- and red-light-emitting perovskite LEDs are around 14 per cent and 12 per cent, respectively-still well behind the performance of organic LEDs and inorganic quantum dot LEDs.