Yuqian Yang

Bio: Yuqian Yang is an academic researcher from Huaqiao University. The author has contributed to research in topics: Perovskite (structure) & Perovskite solar cell. The author has an hindex of 12, co-authored 23 publications receiving 481 citations.

Suppressing Vacancy Defects and Grain Boundaries via Ostwald Ripening for High-Performance and Stable Perovskite Solar Cells.

Abstract: As one kind of promising next-generation photovoltaic devices, perovskite solar cells (PVSCs) have experienced unprecedented rapid growth in device performance over the past few years. However, the practical applications of PVSCs require much improved device long-term stability and performance, and internal defects and external humidity sensitivity are two key limitation need to be overcome. Here, gadolinium fluoride (GdF3 ) is added into perovskite precursor as a redox shuttle and growth-assist; meanwhile, aminobutanol vapor is used for Ostwald ripening in the formation of the perovskite layer. Consequently, a high-quality perovskite film with large grain size and few grain boundaries is obtained, resulting in the reduction of trap state density and carrier recombination. As a result, a power conversion efficiency of 21.21% is achieved with superior stability and negligible hysteresis.

High performance and stable perovskite solar cells using vanadic oxide as a dopant for spiro-OMeTAD

Abstract: Spiro-OMeTAD as a hole-transport material (HTM) plays a crucial role in the photovoltaic performance and stability of perovskite solar cells (PSCs). However, the inferior conductivity and mediocre hole-mobility of unoxidized spiro-OMeTAD limit its function. In order to improve the functional properties of HTMs, we develop a new kind of dopant, vanadic oxide (V2O5) in place of the traditional oxygen in the presence of a lithium salt. V2O5 with strong redox potential can rapidly oxidize spiro-OMeTAD, which effectively improves the hole-transport properties and adjusts the energy level of the HTM. Consequently, the champion PSC based on the V2O5-doped HTM achieves a power conversion efficiency of 20.5%, while the device without V2O5 doping exhibits an efficiency of 18.1% under the same test conditions. Meanwhile, owing to the reduction of trap state density and the band gap adjustment by V2O5 doping the hysteresis of devices is effectively suppressed and the stability is improved. The facile and inexpensive treatment and obvious performance improvement render the present finding very promising.

Towards commercialization: the operational stability of perovskite solar cells

Abstract: Recently, perovskite solar cells (PSCs) have attracted much attention owing to their high power conversion efficiency (25.2%) and low fabrication cost. However, the short lifetime under operation is the major obstacle for their commercialization. With efforts from the entire PSC research community, significant advances have been witnessed to improve the device operational stability, and a timely summary on the progress is urgently needed. In this review, we first clarify the definition of operational stability and its significance in the context of practical use. By analyzing the mechanisms in established approaches for operational stability improvement, we summarize several effective strategies to extend device lifetime in a layer-by-layer sequence across the entire PSC. These mechanisms are discussed in the contexts of chemical reactions, photo-physical management, technological modification, etc., which may inspire future R&D for stable PSCs. Finally, emerging operational stability standards with respect to testing and reporting device operational stability are summarized and discussed, which may help reliable device stability data circulate in the research community. The main target of this review is gaining insight into the operational stability of PSCs, as well as providing useful guidance to further improve their operational lifetime by rational materials processing and device fabrication, which would finally promote the commercialization of perovskite solar cells.