TY - JOUR
T1 - Toward Faster Organic Photodiodes
T2 - Tuning of Blend Composition Ratio
AU - Saggar, Siddhartha
AU - Sanderson, Stephen
AU - Gedefaw, Desta
AU - Pan, Xun
AU - Philippa, Bronson
AU - Andersson, Mats R.
AU - Lo, Shih Chun
AU - Namdas, Ebinazar B.
PY - 2021/5/10
Y1 - 2021/5/10
N2 - The ability of a light-sensor to detect fast variation in incident light intensity is a vital feature required in imaging and data transmission applications. Solution-processed bulk heterojunction (BHJ) type organic photodiodes (OPDs) have gone through key developments, including dark current mitigation and longer linear dynamic range. In contrast, there has been less focus on increasing OPD response speed (f–3dB). Here, bulk heterojunction OPDs based on electron-donating polymer poly[thiophene-2,5-diyl-alt-5,10-bis((2-hexyldecyl)oxy)dithieno[3,2-c:3′,2′-h][1,5]naphthyridine-2,7-diyl] (or PTNT) and electron-accepting phenyl-C71-butyric acid methyl ester (or PC71BM) are reported. The intrinsic charge transport characteristics required for fast speed OPDs are discussed, and an analytical model for the same is developed. The OPDs present 0.8 MHz f–3dB under no applied voltage bias for a typical blend ratio of 1:1 by weight. It is shown that balanced electron and hole mobility is a critical criterion for faster speed OPDs, which can be realized by tuning the composition ratio of the bulk heterojunction. By tuning PTNT and PC71BM blend ratio, the f–3dB was successfully raised by more than quadruple to 4.5 MHz. The findings provide a tool to set device architecture for faster next-generation light sensors.
AB - The ability of a light-sensor to detect fast variation in incident light intensity is a vital feature required in imaging and data transmission applications. Solution-processed bulk heterojunction (BHJ) type organic photodiodes (OPDs) have gone through key developments, including dark current mitigation and longer linear dynamic range. In contrast, there has been less focus on increasing OPD response speed (f–3dB). Here, bulk heterojunction OPDs based on electron-donating polymer poly[thiophene-2,5-diyl-alt-5,10-bis((2-hexyldecyl)oxy)dithieno[3,2-c:3′,2′-h][1,5]naphthyridine-2,7-diyl] (or PTNT) and electron-accepting phenyl-C71-butyric acid methyl ester (or PC71BM) are reported. The intrinsic charge transport characteristics required for fast speed OPDs are discussed, and an analytical model for the same is developed. The OPDs present 0.8 MHz f–3dB under no applied voltage bias for a typical blend ratio of 1:1 by weight. It is shown that balanced electron and hole mobility is a critical criterion for faster speed OPDs, which can be realized by tuning the composition ratio of the bulk heterojunction. By tuning PTNT and PC71BM blend ratio, the f–3dB was successfully raised by more than quadruple to 4.5 MHz. The findings provide a tool to set device architecture for faster next-generation light sensors.
KW - cutoff frequency
KW - polymer photodiodes
KW - response speed
UR - http://www.scopus.com/inward/record.url?scp=85101833644&partnerID=8YFLogxK
UR - http://purl.org/au-research/grants/ARC/DP200103036
UR - http://purl.org/au-research/grants/ARC/DP170102467
U2 - 10.1002/adfm.202010661
DO - 10.1002/adfm.202010661
M3 - Article
AN - SCOPUS:85101833644
VL - 31
JO - Advanced Functional Materials
JF - Advanced Functional Materials
SN - 1616-301X
IS - 19
M1 - 2010661
ER -