Application of Metallocenes in Lead-Free Tin Perovskite Optoelectronics

在短短十多年的研究中，钙钛矿型太阳能电池(PSCs)已经成为一种令人兴奋的新光伏技术。自2009年首次发表关于PSC的报告以来，功率转换效率(PCE)已从3.8%提高到25.5%，使PSC成为迄今为止增长最快的光伏技术。然而，目前需要铅(铅)才能实现高效率。因此，铅钙钛矿器件的广泛商业规模引发了人们对铅可能造成的潜在健康和环境危害的重大担忧。这使得开发无铅和环境友好的钙钛矿替代品成为当务之急。该项目解决了这一重要问题。锡(锡)基钙钛矿是一种有吸引力的铅替代物。然而，锡钙钛矿太阳电池的性能和稳定性仍然落后于铅基系统。这些挑战是众所周知的：(I)薄膜形态差，需要建立新的处理方法来获得高度结晶、无缺陷的薄膜，以及(Ii)Sn2+快速氧化为Sn4+，导致自掺杂和形成锡空位，从而稳定性差[1]。本项目将重点使用茂金属为基础的还原剂添加剂(在薄膜加工步骤和后处理)来控制缺陷浓度、薄膜形貌，以提高器件的性能(功率转换效率和稳定性)。将使用一系列实验表征技术，包括时间分辨光学光谱来探测钙钛矿材料和异质结中的电荷转移动力学。这些研究将得到器件制造和光电分析的补充。在这里，我们将阐明定量的结构-功能关系，这些关系可以用来指导高性能兼容新材料的开发。这项研究的结果将适用于目前采用无铅锡基钙钛矿的一系列设备(例如LED、光电二极管、传感器和太阳能电池)。参考文献：[1]L.Lanzetta，T.Webb等，NAT。交警。12,2853，(2021)。

: In just over a decade of research, perovskite solar cells (PSCs) have emerged as an exciting new PV technology. Since the first publication on PSCs in 2009, the power conversion efficiencies (PCE) have gone from 3.8 to 25.5 %, making PSCs the fastest growing PV technology to date. However, lead (Pb) is currently required to achieve high efficiencies. As such, the widespread commercial scaleup of Pb perovskite devices raises major concerns in relation to potential health and environmental hazards that Pb may cause. This makes the development of Pb-free and environmentally friendly perovskite alternatives a high priority. This project addresses this important issue. Tin (Sn) based perovskites have emerged as an attractive alternative to Pb. However, the performance and stability of Sn perovskite solar cells still lags behind that Pb-based systems. The challenges are well known: (i) poor film morphology and the need to establish new processing methods to achieve highly crystalline, defect-free films and (ii) the rapid oxidation of Sn2+ to Sn4+, resulting in self-doping and the formation of Sn vacancies and thus poor stability [1]. This project will focus on the use of metallocene-based reductant additives (in the film processing step and post-treatments) to control both the defect concentration, film morphology to improve device performance (power conversion efficiency and stability). A range of experimental characterization techniques will be used including time resolved optical spectroscopy to probe charge transfer dynamics in perovskite materials and heterojunctions. These studies will be complimented by device fabrication and optoelectronic analysis. Herein, we will elucidate quantitative structure-function relationships that can be used to guide the development of new materials compatible with high performance. The outputs of this research will be applicable to a range of devices (e.g. LEDs, photodiodes, sensors as well as solar cells) now employing lead-free, Sn-based perovskite.References:[1] L. Lanzetta, T. Webb et al., Nat. Commun. 12, 2853, (2021).