Effective Strategy for High-Performance Organic Photodetectors with Significantly Suppressed Dark Current and Improved Responsivity

Abstract

Organic photodetectors (OPDs) have attracted immense interest as solution-processable optical signal-capturing devices due to their various advantages, such as adjustable response range, excellent weak light response, lightweight, flexibility, and ease of processing on diverse substrates. Low dark current density (J_d) and high responsivity (R) are key requirements necessary for achieving a high specific detectivity (D*). Here, an effective strategy for preparing high-performance OPDs with potential micro p-i-n structure by introducing insulating poly(aryl ether) (PAEN) into the organic photosensitive layer is reported. The PM6:PC₇₁BM-based OPDs are capable of significantly suppressing J_d while increasing R, which can be attributed to the multiple optimizations of morphology and charge transport caused by the addition of PAEN. As a result, the value of J_d (3.63 × 10⁻¹⁰ A cm⁻²) is two orders of magnitude lower than that of the device without PAEN (1.00 × 10⁻⁸ A cm⁻²) at −1 V bias. Combined with the increased R of 0.376 A W⁻¹, the optimized device achieves a high D*of 3.45 × 10¹³ Jones (−1 V at 620 nm). The optimized OPDs demonstrate high performance that is comparable to commercial Si photodetectors (Hamamatsu S1133), paving the way for the direct market development of this cost-effective organic photodetection technology.