Metal halide perovskite solar cells are emerging candidates amongst the next-generation thin-film photovoltaic devices with extremely low fabrication cost and high power conversion efficiency. Defects (both in the bulk material and at the interfaces) are recognized as one of the most fundamental reasons for the compromised device performance and long-term stability of perovskite solar cells. In this review article, we analyse the possible origins of the defects formation in metal halide perovskites, followed by the rationalization of various approaches being utilized to reduce the density of defects. We demonstrate that defect engineering, including adding dopants in the precursor solutions, interface passivation, or other physical treatments (thermal or light stress) is an essential way to further boost the device performance and enhance their long-term stability. We note that although the exact mechanisms of defect elimination in some approaches are yet to be elucidated, the research on defect engineering is expected to have enormous impact on next wave of device performance optimisation of metal halide perovskite solar cells towards Shockley-Queisser limit.
Metal halide perovskite solar cells are emerging candidates for next?generation thin?film photovoltaic devices with the potential for extremely low fabrication cost and high power conversion efficiency. Perovskite solar cells have demonstrated a rapid development in device performance over the last decade, from an initial 3.81% to a most recently certified 24.2%, though the challenges of long?term stability and lead toxicity still remain. Carbon materials, ranging from zero?dimensional carbon quantum dots to three?dimensional carbon black materials, are promising candidates for the enhancement of both efficiency and stability of perovskite solar cells, offering unique advantages for incorporation into various device architectures. In this review article, we present a concise overview of important and exciting advancements of perovskite solar cells that incorporate different dimensions of carbon material in their device architectures in an effort to simultaneously improve device performance and long?term stability. We also discuss the major advantages and potential challenges of each technique that has been developed in the most recent work. Finally, we outline the future opportunities toward more efficient and stable perovskite solar cells utilizing carbon materials.
Li Bowei, Xiang Yuren, Jayawardena Imalka, Luo Deying, Watts John, Hinder Steven, Li Hui, Ferguson Victoria, Luo Haitian, Zhu Rui, Silva Ravi, Zhang Wei (2020) Tailoring Perovskite Adjacent Interfaces by Conjugated Polyelectrolyte for Stable and Efficient Solar Cells,Solar RRL
Interface engineering is an effective means to enhance the performance of thin?film devices, such as perovskite solar cells (PSCs). Herein, a conjugated polyelectrolyte, poly[(9,9?bis(32?((N,N?dimethyl)?N?ethyl?ammonium)?propyl)?2,7?fluorene)?alt?2,7?(9,9?dioctylfluorene)]di?iodide (PFN?I), is used at the interfaces between the hole transport layer (HTL)/perovskite and perovskite/electron transport layer simultaneously, to enhance the device power conversion efficiency (PCE) and stability. The fabricated PSCs with an inverted planar heterojunction structure show improved open?circuit voltage (Voc), short?circuit current density (Jsc), and fill factor, resulting in PCEs up to 20.56%. The devices maintain over 80% of their initial PCEs after 800 h of exposure to a relative humidity 35?55% at room temperature. All of these improvements are attributed to the functional PFN?I layers as they provide favorable interface contact and defect reduction.