Stable Light‐Emitting Diodes Using Phase‐Pure Ruddlesden–Popper Layered Perovskites

Abstract

State-of-the-art light-emitting diodes (LEDs) are made from high-purity alloys of III-V semiconductors, but high fabrication cost has limited their widespread use for large area solid-state lighting. Here, efficient and stable LEDs processed from solution with tunable color enabled by using phase-pure 2D Ruddlesden-Popper (RP) halide perovskites with a formula (CH (CH ) NH ) (CH NH ) Pb I are reported. By using vertically oriented thin films that facilitate efficient charge injection and transport, efficient electroluminescence with a radiance of 35 W Sr cm at 744 nm with an ultralow turn-on voltage of 1 V is obtained. Finally, operational stability tests suggest that phase purity is strongly correlated to stability. Phase-pure 2D perovskites exhibit >14 h of stable operation at peak operating conditions with no droop at current densities of several Amperes cm in comparison to mixtures of 2D/3D or 3D perovskites, which degrade within minutes.

Organic–inorganic metal halide hybrids beyond perovskites

“…Wang et al demonstrated 2D perovskite-based LEDs with high external quantum efficiencies of up to 11.7%, along with good stability [103]. Vertically oriented thin films of phase pure 2D perovskites were reported to have efficient charge injection and transport, and stable efficient EL with ultralow turn-on voltage ( Figure 5(e-g)) [104]. Furthermore, 2D halide perovskites were also employed to fabricate micro-ring laser arrays that showed high quality factor, high gain, and low threshold [105].…”

Stability of Perovskite Light Sources: Status and Challenges

“…Tsai et al synthesized 2D perovskite with the formula of (BA) 2 (MA) n −1 Pb n I 3 n +1 , and their results indicated that the stability of this LED was strongly correlated with the phase purity. [ 126 ] In addition, the pure 2D perovskite‐based LED showed highly stability after >14 h operation, which was much better than that of the 2D/3D hybrid or 3D perovskite‐based LEDs (degrade within minutes).…”

Manipulating the Phase Distributions and Carrier Transfers in Hybrid Quasi‐Two‐Dimensional Perovskite Films

“…Quasi‐two‐dimensional (2D) Ruddlesden–Popper perovskites (RPP) are quantum‐well like materials, which have attracted considerable research interests recently for the application of light‐emitting diode (LED), solar cell, and photodetector . The chemical formula of RPP is L 2 A n −1 M n Y 3 n +1 , where L is the molecular ligand used as spacer cations such as butylammonium (BA) and phenethylammonium (PEA), A is methylammonium (MA) or formamidinium (FA), M is Pb or Sn, Y is halide anion, and n indicates the number of metal layers sandwiched between organic layers .…”