Strong visible light absorption is essential to achieve high power conversion efficiency in indoor organic photovoltaics (iOPVs). Here, we report iOPVs that exhibit high efficiency with high voltage under excitation by low power indoor lighting. Inverted type organic photovoltaic devices with active layer blends utilizing the polymer donor PPDT2FBT paired with fullerene, perylene diimide, or ring-fused acceptors that are 6.5–9.1% efficient under 1 sun are demonstrated to reach efficiencies from 10 to 17% under an indoor light source. This performance transcends that of a standard silicon photovoltaic device. Moreover, we compared iOPVs with active layers both spin-cast and slot-die cast from nonhalogenated solvents and demonstrate comparable performance. This work opens a path towards high-efficiency iOPVs for low power electronics.

In this contribution we report on solution processed red OLEDs based upon an N-annulated perylene diimide dimer, namely tPDI2N-EH, a red-light emitting molecule.

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This work presents a new device architecture integrating multiple poly(methyl methacrylate) (PMMA) electron‐blocking layers (EBL) in quantum dot light‐emitting diodes (QD‐LEDs). The device utilizes red‐emitting CdSe/ZnS QD with a novel structure where multiple PMMA EBLs are sandwiched between a pair of QD layers. A systematic optimization of QD‐LED structures has shown that a device including two PMMA and three QD layers performs the best, achieving a current efficiency of 17.8 cd A−1 and a luminance of 194 038 cd m−2. Numerical simulation of a simplified model of the proposed QD‐LED structure verifies that the structure consisting of two PMMA and three QD layers provides significant improvement in electroluminescent intensity. The simulation provides further insight into the origin of the effect of the PMMA EBL by showing that the addition of PMMA EBL reduces the electron leakage from the active QD region and enhances electron confinement, leading to an increased electron concentration in the QD active layers and a higher radiative recombination rate. The experimental and theoretical studies presented in this work demonstrate that multiple layers of PMMA can act as efficient EBLs in the fabrication of QD‐LEDs of improved performance.

Flexible red OLEDs based on a quadruple-layer stack, in between electrodes, with 160 mm 2 active area were fabricated in ambient air on PET via slotdie-coating. For the OLED structure PET/ITO/PEDOT:PSS/PVK/PFO:tPDI 2 N-EH/ZnO/Ag, the ink formulations and coating parameters for each layer were systematically evaluated and optimized. The air-stable red-light-emitting material tPDI 2 N-EH was successfully utilized as blended homogeneous film with PFO for the emitting layer. The use of an organic hole-transport layer (PVK) and inorganic electron injection layer (ZnO) significantly improved the brightness of the reference device from 4 to 303 cd/m 2 . Surface analysis using AFM measurements showed that the PVK interlayer reduced the surface roughness of the hole injection layer (PEDOT:PSS) from 0.45 to 0.17 nm, which improved the ability to form uniform emitting layers on top. In addition, the ZnO interlayer decreased surface roughness from 1.26 to 0.85 nm and reduced the turn-on voltage of the device from 5.0 to 2.8 V.