Ultra-Narrow-Band NIR Photomultiplication Organic Photodetectors Based on Charge Injection Narrowing

Ultra-narrow-band NIR photomultiplication organic photodetectors (PM-OPDs) were realized in ITO/PEDOT:PSS/active layers/Al based on an interfacial-trap-induced charge injection narrowing (CIN) concept. The rather less Bod Ethex-Hex (BEH) is imbedded in a polymer donor matrix to form large amounts of isolated electron traps. Trapped electrons in BEH close to an Al electrode will enforce hole-tunneling injection induced by interfacial band bending, resulting in a photomultiplication phenomenon. PM-OPDs with P3HT:BEH as the active layer exhibit a narrow response peak at 850 nm with a full-width at half-maximum (fwhm) of 27 nm as well as a rather weak response from 650 to 800 nm. The EQE of 29 700% at 850 nm was achieved in PM-OPDs by incorporating 0.02 wt % of F(6)TCNNQ under -13 V of applied voltage. The rejection ratio (RR) of the optimized PM-OPDs with F(6)TCNNQ is 11 for EQE(850 nm)/EQE(700 nm) and 10 for EQE(850 nm)/EQE(750 nm), respectively. An EQE of 15 300% at 850 nm was achieved in the ternary PM-OPDs under -13 V of applied voltage, with markedly enhanced RRs of 44 for EQE(850 nm)/EQE(700 nm) and 30 for EQE(850 nm)/EQE(750 nm).

Automated summary

Ultra-narrow-band NIR organic photodetectors with photomultiplication capabilities were developed by narrowing charge injection using interfacial traps. By incorporating BEH and F(6)TCNNQ into the active layers, high EQE values at 850 nm were achieved with improved rejection ratios.