Self‐Aggregated Light‐Trapping Nanodots for Highly Efficient Organic Solar Cells

Abstract

The typical thickness of the photoactive layer in organic solar cells (OSCs) is around 100 nm, which limits the absorption efficiency of the incident light and the power conversion efficiency (PCE) of OSCs. Therefore, light‐trapping schemes to reduce the optical losses in the thin photoactive layers are critically important for efficient OSCs. Herein, light‐trapping and electron‐collection dual‐functional small organic molecules, N,N,N′,N′‐tetraphenyloxalamide (TPEA) and N,N,N′,N′‐tetraphenylmalonamide (TPMA), are designed and synthesized by a one‐step acylation reaction. Driven by strong intermolecular force, TPEA and TPMA tend to self‐aggregate into hemispherical light‐trapping nanodots on the photoactive layer, resulting in enhanced light harvesting. Meanwhile, TPEA and TPMA demonstrate high electron mobility and excellent electron‐collection ability. Compared with the device without cathode buffer layer (CBL, PCE = 14.09%), PM6:BTP‐eC9 based OSCs with TPEA and TPMA light‐trapping CBLs demonstrate greatly enhanced PCE of 16.21% and 17.85%, respectively. Furthermore, a record PCE of 19.02% can be achieved for PM6:BTP‐eC9:PC71BM based ternary OSC with TPMA light‐trapping CBL. Moreover, TPMA exhibits a low synthesis cost of only 0.61 $ g−1 with high yield. These findings could open a window for the rational design of multifunctional CBLs for efficient and stable OSCs.

Achieving 17.94% efficiency all-polymer solar cells by independently induced D/A orderly stacking

“…The values of s and n of the ternary APSC were closer to unity, indicating that the charge trap-assisted recombination and bimolecular recombination could be effectively suppressed, further elucidating the improvement of the FF. [47][48][49] In addition, the transient photocurrent (TPC) and transient photovoltage (TPV) were also measured to further investigate the charge-transport dynamics of the APSCs, as presented in Fig. 4(b) and (c).…”

Quinoxaline-based nonfullerene acceptors with powerful core-functionalization ability enabling efficient solar energy utilization

“…Solar energy utilization has been considered as one of the promising renewable technologies due to the various merits of inexhaustible source, cleanness, safety, and high efficiency, showing widespread and versatile applications in photovoltaic, photothermal, and chemical energy conversion fields. [1][2][3][4][5][6][7][8][9][10] The p-conjugated nonfullerene electron acceptors (NFAs) composed of alternating electron-deficient and -rich units have triggered wide interest in solar energy exploitation because of their facile a Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of synthesis, structural diversity, controllable optoelectronic properties, and high mechanical flexibility. [11][12][13][14][15][16][17] The emergence of a star acceptor (ITIC) reported by Zhan's group has significantly promoted the development of NFAs, representing a milestone.…”

Substrate Interface Engineering for Drastically Boosted Short-Circuit Current Density and Fill Factor in Perovskite Solar Cells

“…30−32 Enhancing light-trapping schemes via self-aggregated nanodots and metal chelates has also been reported in solar cells. 33,34 These complex and expensive processes are inconvenient and incompatible for scale production and commercialization for solar cells. To the best of our knowledge, enhancing the device photovoltaic performance by improving the photon transmission of ITO has not been reported in the PSC community.…”

“…Typical strategies to improve the optical transmission of ITO in other fields have been focused on making an artificial nanoscale surface structure or constructing a multilayer ITO film with a combination of different refractive indexes and thicknesses. These reported artificial nanoscale structures such as arrays of nanowhiskers, nanorods, and nanowires on the ITO surface were fabricated under harsh and expensive conditions and sensitive to deposition parameters such as the deposition rate, deposition angle, rotation of substrate or source, deposition temperature, etc. − An antireflection multilayer ITO film achieved by different deposition or sputtering methods faced similar processing cost issues. − Enhancing light-trapping schemes via self-aggregated nanodots and metal chelates has also been reported in solar cells. , These complex and expensive processes are inconvenient and incompatible for scale production and commercialization for solar cells. To the best of our knowledge, enhancing the device photovoltaic performance by improving the photon transmission of ITO has not been reported in the PSC community.…”