Chen Weijie

Nature Photonics, Published online: 18 July 2022; doi:10.1038/s41566-022-01033-8

Publication date: October 2022

Source: Nano Energy, Volume 101

Author(s): Tingming Jiang, Xuehui Xu, Zeshun Lan, Zeng Chen, Xu Chen, Tianyu Liu, Siyuan Huang, Yang (Michael) Yang

Light management to maximize external luminescence efficiency and photon absorptivity and methodology for enthalpy-driven thermodynamic phase stability are future research directions toward extremely efficient and stable perovskite solar cells approaching theoretical power conversion efficiency.

Abstract

As power conversion efficiency (PCE) of perovskite solar cells (PSCs) has rapidly increased up to 25.7% in 2022, a curiosity about the achievable limit of the PCE has prevailed and demands understanding about the underlying fundamentals to step forward. Meanwhile, outstanding long-term stability of PSCs over 1000 h has been reported at operating conditions or under damp heat test with 85 °C/85% relative humidity. Herein comes the question as to whether the phase stability issue of perovskite crystal is completely resolved in the most recent state-of-the-art perovskite film or if it deceives everyone into believing so by significantly slowing the kinetics. On the one hand, the fundamental origins of a discrepancy between reported values and the theoretical limit are thoroughly examined, where the importance of light management is greatly emphasized with the introduction of external luminescence as a key parameter to narrow the gap. On the other hand, the phase stability of a perovskite film is understood from thermodynamic point of view to address viable approaches to lower the Gibbs free energy, distinguishing the kinetically trapped condition from the thermodynamically stable phase.

Hot casting is shown to allow for reduced loading of dimethyl sulfoxide (DMSO) in perovskite precursor inks, and remnant DMSO in films. This suppresses formation of undesired byproducts. The resulting perovskite layers show fewer defects, while their solar cells exhibit superior operational stability under considerable UV-containing simulated solar exposure over 3000 h.

Abstract

High-performance inorganic–organic lead halide perovskite solar cells (PSCs) are often fabricated with a liquid additive such as dimethyl sulfoxide (DMSO), which retards crystallization and reduces roughness and pinholes in the perovskite layers. However, DMSO can be trapped during perovskite film formation and induce voids and undesired reaction byproducts upon later processing steps. Here, it is shown that the amount of residual DMSO can be reduced in as-spin-coated films significantly through use of preheated substrates, or a so-called hot-casting method. Hot casting increases the perovskite film thickness given the same concentration of solutions, which allows for reducing the perovskite solution concentration. By reducing the amount of DMSO in proportion to the concentration of perovskite precursors and using hot casting, it is possible to fabricate perovskite layers with improved perovskite–substrate interfaces by suppressing the formation of byproducts, which increase trap density and accelerate degradation of the perovskite layers. The best-performing PSCs exhibit a power conversion efficiency (PCE) of 23.4% (23.0% stabilized efficiency) under simulated solar illumination. Furthermore, encapsulated devices show considerably reduced post-burn-in decay, retaining 75% and 90% of their initial and post-burn-in efficiencies after 3000 h of operation with maximum power point tracking (MPPT) under high power of ultraviolet (UV)-containing continuous light exposure.

Publication date: October 2022

Source: Nano Energy, Volume 101

Author(s): Ali Hassan, Zhijie Wang, Yeong Hwan Ahn, Muhammad Azam, Abbas Ahmad Khan, Umar Farooq, Muhammad Zubair, Yu Cao

Publication date: October 2022

Source: Nano Energy, Volume 101

Author(s): Fabio Matteocci, Daniele Rossi, Luigi Angelo Castriotta, Daniel Ory, Salim Mejaouri, Matthias Auf der Maur, Frédéric Sauvage, Stefania Cacovich, Aldo Di Carlo

Publication date: October 2022

Source: Nano Energy, Volume 101

Author(s): Xiaodong Hu, Cheng Zhu, Wenjun Zhang, Haixin Wang, Jianan Wang, Fumeng Ren, Rui Chen, Sanwan Liu, Xin Meng, Jing Zhou, Yongyan Pan, Xueying Tian, Derun Sun, Shasha Zhang, Yiqiang Zhang, Zonghao Liu, Qi Chen, Wei Chen

Publication date: 20 July 2022

Source: Joule, Volume 6, Issue 7

Author(s): Xinjing Huang, Dejiu Fan, Yongxi Li, Stephen R. Forrest

Publication date: 17 August 2022

Source: Joule, Volume 6, Issue 8

Author(s): Dongchen Lan, Martin A. Green