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Recently, perovskite solar cells (PSCs) and organic solar cells (OSCs) have emerged as solution-processable photovoltaic (PV) technologies with certified power conversion efficiencies (PCEs) surpassing 26% and 20%, respectively. However, challenges such as charge generation, separation, transport, collection, and recombination at the nanoscale still exist in fully controlling and understanding the performance-limiting factors in the photoactive layers of OSC and PSC devices. Although several efforts have been reported to address the above phenomena, the origin of the nanoscale defects and how they lead to performance losses have not yet been fully understood. This perspective provides an in-depth discussion of nanoscale spatial and time-resolved mapping for OSCs and PSCs to understand their roles in improving PV performance. A comprehensive multimodal technique to map the charge carrier photodynamics at the nanoscale, such as charge generation, separation, transport, collection, and recombination in OSCs and PSCs, is presented, which has the potential to evaluate the photodynamics related to local heterogeneities in the active layers of the corresponding devices. [ABSTRACT FROM AUTHOR]

Perovskite solar cells (PSCs) have made great strides in recent years, operating inside the theoretical Scholkely–Quisser efficiency limit with a certified power conversion efficiency (PCE) of 26.1%. However, lead toxicity from Pb‐based PSCs can harm the environment. As a result, the search for nontoxic and environmentally friendly substances to replace Pb in perovskites is the need of the hour. Tin has emerged as the most viable choice to replace Pb, due to its favorable electronic properties and smaller bandgaps of Sn‐based perovskites between 1.1 and 1.4 eV, strong charge carrier mobility, and high theoretical efficiency of 32%. Sn vacancies and point defects, on the other hand, are easily produced in Sn perovskites, leading to nonradiative recombination. Furthermore, interfacial flaws and traps impede further performance improvement. In this research, to produce high‐quality Pb‐free perovskites for high‐performance PSCs, a Lewis‐base thioacetamide (TAA) is added to the simple FASnI3 perovskite solution. FASnI3 and TAA additive‐based films effectively control perovskite film crystallinity and grain size via Lewis acid–base reaction. The champion FASnI3 + TAA‐based PSC achieves a maximum PCE of 10.67% while paving a facile way for other compositional perovskite analogues to be integrated into highly efficient and operationally stable PSCs. [ABSTRACT FROM AUTHOR]

Organic solar cells (OSCs) are viable power sources for photovoltaic applications. In this work, a nonfullerene acceptor, PDI-EH, was designed to form a nearly orthogonal structure to suppress its aggregation, and integrated into ternary OSCs. In addition to enhanced photon absorption and matched charge cascade, a PDI-EH acceptor modulated the morphology, which is crucial to affect device efficiency. Detailed analysis revealed that PDI-EH can fine-tune the miscibility of the host donor and acceptor (D/A) materials to form an optimally intermixed phase with short-range molecular order. Photo-induced force microscopy (PiFM) for selective PiFM imaging of D/A materials provided strong evidence that D/A materials formed well-mixed films after PDI-EH incorporation. Additionally, nanoscale spatial mapping of charge carrier dynamics was realized for the first time in a ternary film using a novel transient photo-response atomic force microscopy (TP-AFM) technique. The resulting TP-AFM data revealed a reduced charge transport time, increased charge recombination lifetime and extended charge diffusion length. These improvements brought about by PDI-EH benefit the photovoltaic performance of ternary OSCs under both 1-sun and indoor illuminations. Our work offers insights into morphology modulation and the resulting local charge carrier dynamic, thereby facilitating the development of OSCs in practical applications. [ABSTRACT FROM AUTHOR]