Design, synthesis and properties of a new near-infrared small molecule acceptor for organic photodetector

High Detectivity Near Infrared Organic Photodetectors Using an Asymmetric Non-Fullerene Acceptor for Optimal Nanomorphology and Suppressed Dark Current

“…Assuming that the shot noise in J D is the dominant parameter contributing to the total noise of the OPDs, shot-noise-limited detectivity ( D sh *) can be obtained according to the relationship, D sh * = R /(2 qJ D ) 1/2 . , Figure a shows spectral D sh * at −0.1 V wherein YOR1-OPD exhibited an overall superior D * level at the NIR regime to YOR2-OPD due to considerably reduced J D and elevated R in YOR1-OPD. It is noteworthy that the D sh * values of YOR1-OPD at 950 and 1000 nm were 1.98 × 10 13 and 3.38 × 10 12 Jones, respectively, which are among the highest values for NIR OPDs that simultaneously satisfy high D * at both wavelengths (Figure c). ,,,,,,,− In contrast, the YOR2-OPD exhibited significantly lower D sh * values of 1.31 × 10 11 and 3.99 × 10 10 Jones at 950 and 1000 nm, respectively, because of the relatively high J D and low R values. Figure d compares the spectral D sh * of YOR1- and YOR2-OPDs, and their detailed PD parameters are summarized in Table .…”

“…COM-based low- E g nonfullerene acceptors (NFAs) have emerged as efficient absorbers for bulk heterojunction (BHJ) film-based NIR OPDs. − They possess the beneficial optical and electrical properties, such as strong and tunable NIR light absorption characteristics and efficient charge transport capability as an electron acceptor. − Y6 and Y6BO, widely used NIR-absorbing NFAs, exhibited strong NIR absorption with a narrow E g (Y6: 1.31 eV and Y6BO: 1.36 eV). ,− Unfortunately, NIR OPDs comprising Y6 and Y6BO showed a very low response to a longer NIR region (>950 nm) because their absorbance abruptly decreases over approximately 860 nm (cf. λ max,Y6 : 858 nm and λ max,Y6BO : 824 nm). ,,, Thereby, much research on the development of NFAs having an effective photoresponse at >950 nm has been conducted using Y6-framework. ,,− Among them, DO-4F is recognized as a promising NIR-absorbing NFA due to the high NIR absorbance, low dark current density ( J D ), high specific detectivity ( D *), and responsivity ( R ) of DO-4F-based OPDs. However, the absorption spectrum still cannot exceed 1000 nm, limiting long wavelength NIR OPD applications.…”

Organic photodetectors: materials, device, and challenges

“…65 These device parameters are competitive with the performance of other single-layer organic heterojunction photodetectors reported from visible to NIR regions. [66][67][68][69] In addition to broadening the absorption spectrum, the tandem structure can also be used to achieve narrow-band OPDs with a dual-wavelength response by utilizing the narrow absorption range of organic semiconductors. Wang et al designed a tandem structure shown in Fig.…”

“…6(b)). 65,72,[74][75][76][77][78][79][80][81] It is worth mentioning that the complex device structure will inevitably lead to a corresponding increase in processing costs of organic tandem photodetectors as shown in Fig. 7, which may place great restrictions on their commercial applications.…”

“…65 These device parameters are competitive with the performance of other single-layer organic heterojunction photodetectors reported from visible to NIR regions. 66–69…”