Efficient and stable blue perovskite light-emitting diodes through I-III-VI quantum dot solids as hole transport layer

Perovskite light-emitting diodes (PeLEDs) have achieved skyrocketing progress in material and device efficiencies. However, inferior stabilities of pure blue devices, remain major hurdles towards full-color displays. Herein, we built PeLEDs based on quasi-two-dimensional (quasi-2D) perovskites using chalcopyrite I-III-VI semiconductor quantum dot (QD) solids as novel inorganic hole transport layer (HTL), to overcome the stability issues in blue PeLEDs. Wide-gap silver-copper-gallium-disulfide (ACGS) QDs were dedicatedly-synthesized aiming for enhanced hole transport efficiency in QD solids through adaptable band structure and surface chemistry engineering, resulting in band-like hole transport with a high mobility of 0.546 cm ² V ^− 1 s ^− 1 in the linear working scheme. In addition, the Lewis base group attached to the QD surface (Cl ⁻ , RS ⁻ ) lower the defect density through buried interface passivation on uncoordinated Pb ²⁺ in perovskite, which effectively regulate crystallization kinetics of quasi-2D perovskite. Furthermore, halide interstitial defects were stabilized by Lewis acids group (Zn ²⁺ ) capped on the surface of ACGS QDs, preventing ionic migration and deep-level trap formation. As a result, the champion pure-blue PeLEDs based on ACGS QD solids exhibit preeminent operating lifetime (T ₅₀ @100 cd/m ²  = 78 min) for electroluminescence (EL) peak emission wavelength at 471 nm, with maximum external quantum efficiency (EQE) of 10.85%.