Chiang Chien-Hung, Kan Chun-Wei, Wu Chun-Guey
Department of Chemistry, National Central University, Jhong-Li, Chung-Li 32001, Taiwan.
Research Center for New Generation Light Driven Photovoltaic Modules, National Central University, Jhong-Li, Chung-Li 32001, Taiwan.
ACS Appl Mater Interfaces. 2021 May 26;13(20):23606-23615. doi: 10.1021/acsami.1c02105. Epub 2021 May 11.
A simple, synergistic engineering of the conduction band (CB), conductivity, and interface of TiO-based bilayered electron transport layers (ETLs) via scalable TiO and SnO nanoparticles processed at low temperature (≤ 100 °C) for regular planar perovskite solar cells (PSCs) was developed. The bottom layer (Lt-TiO:SnO nanocomposite film) was prepared by spin coating from the ethanol suspension of small ground TiO nanoparticles with big ground SnO nanoparticles as the additive. The top C-SnO layer (spin-coated from the concentrated commercial SnO nanoparticles (C-SnO NPs, 20 wt %, 7 nm in size suspended in HO)) can be regarded as an interlayer between Lt-TiO:SnO and perovskite (Psk) absorbers. Bilayered Lt-TiO:SnO/C-SnO ETLs are dense films with a cascade CB, good conductivity, facile electron extraction/transport ability, and a highly hydrophilic surface for depositing high-quality Psk films. Regular planar PSCs based on Lt-TiO:SnO/C-SnO ETLs combined with a (FAI)(PbI)(MABr)(PbBr) absorber and a spiro-OMeTAD hole transporter achieved the highest power conversion efficiency of 22.04% with a negligible current hysteresis. The champion cell lost less than 3% of the initial efficiency under continuous room lighting (1000 lux) for 1000 h (lost 10% after 2184 h) without encapsulation under an inert atmosphere. Four related low-temperature-processed ETLs (Lt-TiO/C-SnO, Lt-C-SnO, Lt-TiO:SnO, and Lt-TiO) were fabricated using the same metal oxide nanoparticle suspensions and studied simultaneously to reveal the function of each metal oxide in the bilayered Lt-TiO:SnO/C-SnO ETLs. In the bottom Lt-TiO:SnO layer, small TiO nanoparticles were needed for making a dense film, and highly conducting big SnO nanoparticles are used to increase the conductivity of ETLs and a handy electron transport path for reducing the charge accumulation and series resistance of the cell. A top C-SnO layer (regarded as an interlayer between Psk and Lt-TiO:SnO) was used to extract/transport electrons facilely, to form a bilayered ETL with a cascade CB, and to create a hydrophilic surface to deposit high-quality Psk films to enhance the photovoltaic performance of the PSCs. This study provides a blueprint for designing good-performance ETLs for high-efficiency, stable regular planar PSCs using various sized nanoparticles prepared in a very simple and low-cost way.
通过在低温（≤100°C）下对可扩展的TiO和SnO纳米颗粒进行处理，开发了一种简单的、具有协同作用的工程方法，用于常规平面钙钛矿太阳能电池（PSC）的TiO基双层电子传输层（ETL）的导带（CB）、导电性和界面。底层（Lt-TiO:SnO纳米复合膜）通过旋涂由研磨后的小TiO纳米颗粒的乙醇悬浮液和研磨后的大SnO纳米颗粒作为添加剂制备而成。顶部的C-SnO层（由浓缩的商业SnO纳米颗粒（C-SnO NPs，20 wt%，尺寸为7 nm，悬浮在H₂O中）旋涂而成）可被视为Lt-TiO:SnO和钙钛矿（Psk）吸收体之间的中间层。双层Lt-TiO:SnO/C-SnO ETL是致密的薄膜，具有级联CB、良好的导电性、便捷的电子提取/传输能力以及用于沉积高质量Psk薄膜的高亲水性表面。基于Lt-TiO:SnO/C-SnO ETLs、结合（FAI）（PbI₂）（MABr）（PbBr₂）吸收体和螺环-OMeTAD空穴传输体的常规平面PSC实现了22.04%的最高功率转换效率，且电流滞后可忽略不计。在惰性气氛下不封装的情况下，冠军电池在连续室内照明（1000勒克斯）1000小时内初始效率损失不到3%（2184小时后损失10%）。使用相同的金属氧化物纳米颗粒悬浮液制备并同时研究了四种相关的低温处理ETL（Lt-TiO/C-SnO、Lt-C-SnO、Lt-TiO:SnO和Lt-TiO），以揭示双层Lt-TiO:SnO/C-SnO ETLs中每种金属氧化物的功能。在底部的Lt-TiO:SnO层中，需要小的TiO纳米颗粒来形成致密薄膜，而高导电性的大SnO纳米颗粒用于提高ETL的导电性，并提供便捷的电子传输路径，以减少电池的电荷积累和串联电阻。顶部的C-SnO层（被视为Psk和Lt-TiO:SnO之间的中间层）用于轻松提取/传输电子，形成具有级联CB的双层ETL，并创建一个亲水性表面以沉积高质量的Psk薄膜，从而提高PSC的光伏性能。本研究为使用以非常简单和低成本方式制备的各种尺寸纳米颗粒设计用于高效、稳定常规平面PSC的高性能ETL提供了蓝图。
