High performance and stable perovskite optoelectronic and photonic devices
Ni Zhao a
a Department of Electronic Engineering, The Chinese University of Hong Kong
Proceedings of Device Physics Characterization and Interpretation in Perovskite and Organic Materials (DEPERO)
València, Spain, 2023 October 3rd - 5th
Organizers: Sandheep Ravishankar, Juan Bisquert and Evelyne Knapp
Invited Speaker, Ni Zhao, presentation 026
Publication date: 14th September 2023

Organic-inorganic hybrid perovskites (OIHPs) are a fascinating class of semiconductors that can be low-temperature synthesized, crystallized and processed on a large variety of substrates, and at the same time offering outstanding optical and electronic properties, such as broadband spectral tunability, high defect tolerance, high absorption/emission efficiency, room-temperature excitons, etc. These advantages allow OIHPs to complement conventional inorganic semiconductors (e.g., Si and GaAs) in photonics applications that require low-cost, large active area, wide spectral or polarization tunability or flexibility in substrate selection. In this talk I will give a few examples on OIHP based photonic devices, including LEDs, photodetectors and lasers. First, I will discuss how the notorious instability problems of OIHP LEDs may be addressed through surface molecular passivation. By treating the perovskite surface with phenylalkylammonium iodides (PAAIs), molecules consisting of a benzene ring, an alkyl chain and an amine tail we managed to simultaneously achieve a record T50 half-lifetime of 130 hrs under 100 mA/cm2 (accelerated testing) and a record radiance of 1282.8 W/(sr × m2) for near-IR OIHP LEDS. The finding of the PAAI was enabled by a fundamental study combining experimental characterization and theoretical modelling, which reveals that the stabilization effect of the passivation is governed by the steric hindrance of the molecules to reconfiguration for accommodating ion migration from the perovskite surface. Secondly, I will focus on the commonly seen gain – bandwidth trade-off problem of photodetectors and introduce a monolithically integrated photovoltaic transistor (PVT) design to solve this dilemma. The PVT exploiting a lead halide perovskite as the photoactive layer achieved a record high gain – bandwidth product of ~ 1011. Finally, I will talk about our recent exploration of using quasi-two-dimensional Dion-Jacobson (DJ) phase perovskites for laser application. With properly selected organic spacers, DJ phase OIHPs offer excellent chemical resistance and thermal processability. These properties allow us to achieve optically pumped perovskite lasers with record-high quality factor, record-low lasing threshold and excellent operational stability.

The studies presented here were supported by the Excellent Young Scientists Fund from National Natural Science Foundation of China (62022004) and General Research Fund from Hong Kong Research Grants Council (14207221 and 14209620).

We use our own and third party cookies for analysing and measuring usage of our website to improve our services. If you continue browsing, we consider accepting its use. You can check our Cookies Policy in which you will also find how to configure your web browser for the use of cookies. More info