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Herein, a new ternary strategy to fabricate efficient and photostable inverted organic photovoltaics (OPVs) is introduced by combining a bulk heterojunction (BHJ) blend and a fullerene self‐assembled monolayer (C60‐SAM). Time‐of‐flight secondary‐ion mass spectrometry ‐ analysis reveals that the ternary blend is vertically phase separated with the C60‐SAM at the bottom and the BHJ on top. The average power conversion efficiency ‐ of OPVs based on the ternary system is improved from 14.9% to 15.6% by C60‐SAM addition, mostly due to increased current density (Jsc) and fill factor ‐. It is found that the C60‐SAM encourages the BHJ to make more face‐on molecular orientation because grazing incidence wide‐angle X‐ray scattering ‐ data show an increased face‐on/edge‐on orientation ratio in the ternary blend. Light‐intensity dependent Jsc data and charge carrier lifetime analysis indicate suppressed bimolecular recombination and a longer charge carrier lifetime in the ternary system, resulting in the enhancement of OPV performance. Moreover, it is demonstrated that device photostability in the ternary blend is enhanced due to the vertically self‐assembled C60‐SAM that successfully passivates the ZnO surface and protects BHJ layer from the UV‐induced photocatalytic reactions of the ZnO. These results suggest a new perspective to improve both performance and photostability of OPVs using a facial ternary method. [ABSTRACT FROM AUTHOR]

Herein, we design and characterize 9-heterocyclic ring non-fullerene acceptors (NFAs) with the extended backbone of indacenodithiophene by cyclopenta [2,1-b:3,4-b'] dithiophene (CPDT). The planar conjugated CPDT donor enhances absorption by reducing vibronic transition and charge transport. Developed NFAs with different end groups shows maximum absorption at approximately 790–850 nm in film. Because of the electronegative nature of the end-group, the corresponding acceptors showed deeper LUMO energy levels and red-shifted ultraviolet absorption. We investigate the crystallinity, film morphology, surface energy, and electronic as well as photovoltaic performance. The organic photovoltaic cells using novel NFAs with the halogen end groups fluorine or chlorine demonstrate better charge collection and faster exciton dissociation than photovoltaic cells using NFAs with methyl or lacking a substituent. Photovoltaic devices constructed from m-Me-ITIC with various end groups deliver power conversion efficiencies of 3.6–11.8%. [ABSTRACT FROM AUTHOR]

Color filters are essential components to realize next‐generation applications based on organic light‐emitting diodes (OLEDs), such as flexible displays and multipurpose lighting. Although the most widely used color filters that include dyes and pigments have advantageous features, such as their simplicity and color purity, the energy wasted by these color filters does not meet the needs for a green and sustainable future. This paper presents a fullerene‐free organic solar cell (OSC) color filter that is not only a highly effective blue color filter, owing to its ability to absorb green and red light, but also functions as an energy‐harvesting device. OLED‐OSC tandem devices with the two distinct functions of OLED and OSC within one device are successfully demonstrated. The OSC of the tandem device generates electrical energy with a power conversion efficiency of 6.83%. The OLED of the tandem device emits blue light with a maximum luminance of 1400 cd m−2, and the International Commission on Illumination (CIE) chromaticity is dramatically tunable from (0.34, 0.36) to (0.14, 0.17). [ABSTRACT FROM AUTHOR]

Despite recent breakthroughs in power conversion efficiencies (PCEs), which have resulted in PCEs exceeding 22%, perovskite solar cells (PSCs) still face serious drawbacks in terms of their printability, reliability, and stability. The most efficient PSC architecture, which is based on titanium dioxide as an electron transport layer, requires an extremely high-temperature sintering process (≈500 °C), reveals hysterical discrepancies in the device measurement, and suffers from performance degradation under light illumination. These drawbacks hamper the practical development of PSCs fabricated via a printing process on flexible plastic substrates. Herein, an innovative method to fabricate low-temperature-processed, hysteresis-free, and stable PSCs with a large area up to 1 cm2 is demonstrated using a versatile organic nanocomposite that combines an electron acceptor and a surface modifier. This nanocomposite forms an ideal, self-organized electron transport layer (ETL) via a spontaneous vertical phase separation, which leads to hysteresis-free, planar heterojunction PSCs with stabilized PCEs of over 18%. In addition, the organic nanocomposite concept is successfully applied to the printing process, resulting in a PCE of over 17% in PSCs with printed ETLs. [ABSTRACT FROM AUTHOR]

A new series of ITIC-based non-fullerene acceptors (NFAs), namely m-ITTC-Oeh-SM (IT-SM) and m-ITTC-Oeh-DSM (IT-DSM), which contain thiophene-substituted end groups (EGs) with single and double thiomethyl side chains, respectively, were designed, synthesized, and characterized in this study. The IT-SM NFA exhibited a narrower optical band gap, redshifted absorption, stronger crystallinity, and smoother surface morphology than those of the IT-DSM NFA. Organic solar cells (OSCs) based on the polymer donor PBDB-T and IT-SM reported a power conversion efficiency (PCE) of 8.98% with the addition of 0.5 v/v% 1,8-diiodooctane (DIO), whereas the PCE of the PBDB-T:IT-DSM device was equal to 3.02%. The difference between the PCE values of these two devices was attributed to the gap of the short-circuit current and fill factor. Detailed analyses of the charge transport, collection, and morphology of the blend films were performed to investigate the difference between the device performances. The results of this study can help formulate detailed guidelines for the commercialized production of NFAs. • Novel ITIC-based nonfullerene acceptors with thiophene end groups were synthesized. • Thiomethyl side chains of end group influence the photovoltaic performance. • Synthesized nonfullerene acceptors show PCE of 3.0–9.0% in photovoltaic devices. • The number of side chain strongly influence the morphologies of photoactive layers. [ABSTRACT FROM AUTHOR]