Perovskite solar cells (PSCs) show excellent power conversion efficiencies, long carrier diffusion lengths and low recombination rates. This encourages a view that intragrain defects are electronically benign with little impact on device performance. Here we vary methylammonium (MA)/ formamidinium (FA) composition in MA1-xFAxPbI3 (x=0-1), and compare the structure and density of intragrain planar defects with the device performance, otherwise keeping the device nominally the same. We find charge carrier lifetime, open-circuit voltage-deficit, and current-voltage hysteresis correlate with the density and structure of {111}c planar defects (x=0.5-1) and {112}t twin boundaries (x=0-0.1). The best performance parameters are found when essentially no intragrain planar defects are evident (x=0.2).Similarly, reducing the density of {111}c planar defects using , also improved performance. These observations suggest that intragrain defect control can provide an important route for improving PSCs' performance, in addition to wellestablished parameters, such as grain boundaries and heterojunction interfaces.

This is a repository copy of Achieving over 11% power conversion efficiency in PffBT4T-2OD-based ternary polymer solar cells with enhanced open-circuit-voltage and suppressed charge recombination. . et al. (6 more authors) (2018) Achieving over 11% power conversion efficiency in PffBT4T-2OD-based ternary polymer solar cells with enhanced open-circuit-voltage and suppressed charge recombination. Nano Energy, 44. pp.

Flexible organic solar cells (OSCs) are considered one key component in wearable, intelligent electronics due to the unique capacity for highly flexible renewable energy sources. However, it is urgently required to enhance their efficiency, as it is far inferior to that of their conventional, glass-based counterparts. To boost the performance of flexible OSCs on plastic substrates, we here present a synergetic transparent electrode structure, which combines electrically conductive silver nanowires, a sol–gel-derived ZnO planarization layer, and imprinted light-trapping nanostructures. This synergetic composite electrode exhibits good properties in terms of optical transparency, electrical conductivity, mechanical flexibility, and low-temperature processability. As a result, the single-junction non-fullerene-based flexible OSCs achieve a power conversion efficiency exceeding 12% due to the synergetic interplay between broadband light trapping and suppressed charge recombination loss. Moreover, these flexible OSCs are repeatedly bendable in both inward and outward bending directions, retaining over 60% of the initial efficiency after 1000 cycles of the bending test at a 3.0 mm radius. These results convey a clear depiction of the practicality of flexible OSCs in a variety of high-performance flexible applications.

The photovoltaic performance of inorganic perovskite solar cells (PSCs) still lags behind the organic–inorganic hybrid PSCs due to limited light absorption of wide bandgap CsPbI3‑xBr x under solar illumination. Constructing tandem devices with organic solar cells can effectively extend light absorption toward the long-wavelength region and reduce radiative photovoltage loss. Herein, we utilize wide-bandgap CsPbI2Br semiconductor and narrow-bandgap PM6:Y6-BO blend to fabricate perovskite/organic tandem solar cells with an efficiency of 21.1% and a very small tandem open-circuit voltage loss of 0.06 V. We demonstrate that the hole transport material of the interconnecting layers plays a critical role in determining efficiency, with polyTPD being superior to PBDB-T-Si and D18 due to its low parasitic absorption, sufficient hole mobility and quasi-Ohmic contact to suppress charge accumulation and voltage loss within the tandem device. These perovskite/organic tandem devices also display superior storage, thermal and ultraviolet stabilities.