Ultraviolet (UV) narrowband photodetectors play a critical role in missile detection, flame monitoring, optical communication, etc. It is a great challenge to realize UV narrowband organic photodetectors due to wide photo-harvesting property of organic materials, especially for photomultiplication type organic photodetectors (PM-OPDs). In this work, a smart strategy is proposed to achieve UV narrowband response by coupling Fabry−Pérot microcavity with PM-OPDs. PM-OPDs are realized by using poly(3-hexylthiophene-2,5-diyl):[6,6]-phenyl-C 71 -butyric acid methyl ester (100:1, w/w) as active layers, exhibiting broadband response range covering from UV-vis region. Series of optical microcavities consisting of Ag/LiF/ Ag with UV spectral selectivity are prepared, which are employed to couple with the PM-OPDs for achieving UV narrowband response. The UV spectral selectivity of optical microcavity can be optimized by tuning the thickness of spacer layer and mirror layers, which can further regulate the photogenerated electron distribution near Al electrode to optimize the external quantum efficiency (EQE) spectra of the PM-OPDs coupled with optical microcavity. The optimized PM-OPDs coupled with optical microcavity exhibit EQE of 9300% at 350 nm and narrowband response with 33 nm full-width at halfmaximum under −15 V bias. This work indicates that PM-OPDs coupled with optical microcavity should be an efficient strategy for achieving UV narrowband response.
Layer‐by‐layer organic photovoltaics (LbL‐OPVs) are fabricated using wide bandgap polymer D18 with narrow photon harvesting range in visible light region and narrow bandgap small molecular N3 with strong near‐infrared photon harvesting; the only difference is D18 layer thickness adjusted by spin coating speed. A 15.75% power conversion efficiency (PCE) is obtained from the LbL‐OPVs with D18 layer prepared under 7000 round per minute of spin coating condition; the corresponding D18/N3 layers have a 52.06% of average visible transmittance (AVT) in the spectral range from 370 to 740 nm. Based on the optimized D18/N3 layers, semitransparent LbL‐OPVs are built with 1 nm Au/(10, 15, 20 nm) Ag as the top electrode. The PCE and AVT of semitransparent LbL‐OPVs can be simultaneously adjusted by altering Ag layer thickness due to its variable reflectance and conductivity of top electrode dependence on Ag layer thickness. The PCE/AVT of 12.58%/22.81%, 13.80%/15.09%, and 14.85%/9.48% can be individually achieved from the semitransparent LbL‐OPVs with 10, 15, or 20 nm‐thick Ag layer, which should be among the highest values of semitransparent OPVs based on bulk heterojunction or LbL structures. Adjusting donor layer thickness may be an effective method to construct efficient semitransparent LbL‐OPVs.
In the last few decades, organic solar cells (OSCs) have drawn broad interest owing to their advantages such as being low cost, flexible, semitransparent, non-toxic, and ideal for roll-to-roll large-scale processing. Significant advances have been made in the field of OSCs containing high-performance active layer materials, electrodes, and interlayers, as well as novel device structures. Particularly, the innovation of active layer materials, including novel acceptors and donors, has contributed significantly to the power conversion efficiency (PCE) improvement in OSCs. In this review, high-performance acceptors, containing fullerene derivatives, small molecular, and polymeric non-fullerene acceptors (NFAs), are discussed in detail. Meanwhile, highly efficient donor materials designed for fullerene- and NFA-based OSCs are also presented. Additionally, motivated by the incessant developments of donor and acceptor materials, recent advances in the field of ternary and tandem OSCs are reviewed as well.
Broadband photomultiplication type all-polymer photodetectors (PM-APDs) are achieved on the basis of ITO/PFN-Br/PBDB-T:PYF-T-o (3:100, wt/wt)/LiF/Au as the configuration. Amounts of isolated hole traps are formed with PBDB-T encircled by PYF-T-o...
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