Planar structure of organic photodetector for low dark current

Abstract The focus of this study is on investigating the vanadyl 2,9,16,23-tetraphenoxy-29H, 31H-phthalocyanine (VOPcPhO) and its blend with o-xylenyl C60 bis-adduct (OXCBA), for use as a lateral ultraviolet organic photodetector. The research focuses on improving dark current reduction, which is a challenge in lateral organic photodetector. By integrating the OXCBA, low dark current values of 4.83 nA⋅cm −2 ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msubsup> <mml:mi>D</mml:mi> <mml:mrow> <mml:mi mathvariant="normal">shot</mml:mi> </mml:mrow> <mml:mo>*</mml:mo> </mml:msubsup> <mml:mo>=</mml:mo> <mml:mn>1.414</mml:mn> <mml:mo>×</mml:mo> <mml:msup> <mml:mrow> <mml:mn>10</mml:mn> </mml:mrow> <mml:mrow> <mml:mn>11</mml:mn> </mml:mrow> </mml:msup> <mml:mspace width="0.25em"/> <mml:mi mathvariant="normal">Jones</mml:mi> </mml:mrow> </mml:math> ) have been achieved as compared to the stand-alone VoPcPhO device of 14.06 nA⋅cm −2 . The major contributing factors to dark current reduction are due to the efficient charge transfer at the photoactive-electrode interface, the deep highest occupied molecular orbital (HOMO) level of OXCBA, which leads to favorable energy level alignments hindering hole injection, and the occurrence of bulk heterojunction vertical phase segregation between VOPcPhO and OXCBA. These findings shed light on the relationship between the organic photoconductor’s material composition, morphology, and performance metrics and open new avenues for metal phthalocyanine-based lateral ultraviolet organic photodetectors with low dark current and enhanced performance.