Light-intensity-dependent photoresponse time of organic photodetectors and its molecular origin

Chiara Labanti; Jiaying Wu; Jisoo Shin; Saurav Limbu; Sungyoung Yun; Feifei Fang; Song Yi Park; Chul Joon Heo; Younhee Lim; Taejin Choi; Hyeong Ju Kim; Hyerim Hong; Byoungki Choi; Kyung Bae Park; James R. Durrant; Ji Seon Kim

doi:10.1038/s41467-022-31367-4

Light-intensity-dependent photoresponse time of organic photodetectors and its molecular origin

Chiara Labanti, Jiaying Wu, Jisoo Shin, Saurav Limbu, Sungyoung Yun, Feifei Fang, Song Yi Park, Chul Joon Heo, Younhee Lim, Taejin Choi, Hyeong Ju Kim, Hyerim Hong, Byoungki Choi, Kyung Bae Park, James R. Durrant, Ji Seon Kim

Research output: Contribution to journal › Article › peer-review

4 Citations (Scopus)

Abstract

Organic photodetectors (OPDs) exhibit superior spectral responses but slower photoresponse times compared to inorganic counterparts. Herein, we study the light-intensity-dependent OPD photoresponse time with two small-molecule donors (planar MPTA or twisted NP-SA) co-evaporated with C₆₀ acceptors. MPTA:C₆₀ exhibits the fastest response time at high-light intensities (>0.5 mW/cm²), attributed to its planar structure favoring strong intermolecular interactions. However, this blend exhibits the slowest response at low-light intensities, which is correlated with biphasic photocurrent transients indicative of the presence of a low density of deep trap states. Optical, structural, and energetical analyses indicate that MPTA molecular packing is strongly disrupted by C₆₀, resulting in a larger (370 meV) HOMO level shift. This results in greater energetic inhomogeneity including possible MPTA-C₆₀ adduct formation, leading to deep trap states which limit the low-light photoresponse time. This work provides important insights into the small molecule design rules critical for low charge-trapping and high-speed OPD applications.

Original language	English
Article number	3745
Journal	Nature communications
Volume	13
Issue number	1
DOIs	https://doi.org/10.1038/s41467-022-31367-4
Publication status	Published - 2022 Dec
Externally published	Yes

ASJC Scopus subject areas

Chemistry(all)
Biochemistry, Genetics and Molecular Biology(all)
General
Physics and Astronomy(all)

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10.1038/s41467-022-31367-4

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title = "Light-intensity-dependent photoresponse time of organic photodetectors and its molecular origin",

abstract = "Organic photodetectors (OPDs) exhibit superior spectral responses but slower photoresponse times compared to inorganic counterparts. Herein, we study the light-intensity-dependent OPD photoresponse time with two small-molecule donors (planar MPTA or twisted NP-SA) co-evaporated with C60 acceptors. MPTA:C60 exhibits the fastest response time at high-light intensities (>0.5 mW/cm2), attributed to its planar structure favoring strong intermolecular interactions. However, this blend exhibits the slowest response at low-light intensities, which is correlated with biphasic photocurrent transients indicative of the presence of a low density of deep trap states. Optical, structural, and energetical analyses indicate that MPTA molecular packing is strongly disrupted by C60, resulting in a larger (370 meV) HOMO level shift. This results in greater energetic inhomogeneity including possible MPTA-C60 adduct formation, leading to deep trap states which limit the low-light photoresponse time. This work provides important insights into the small molecule design rules critical for low charge-trapping and high-speed OPD applications.",

author = "Chiara Labanti and Jiaying Wu and Jisoo Shin and Saurav Limbu and Sungyoung Yun and Feifei Fang and Park, {Song Yi} and Heo, {Chul Joon} and Younhee Lim and Taejin Choi and Kim, {Hyeong Ju} and Hyerim Hong and Byoungki Choi and Park, {Kyung Bae} and Durrant, {James R.} and Kim, {Ji Seon}",

note = "Funding Information: We thank Samsung Electronics for the project funding and the UK EPSRC for ATIP program grant (EP/T028513/1) and Center for Doctoral Training in Plastic Electronic Materials (EP/L016702/1). Publisher Copyright: {\textcopyright} 2022, The Author(s).",

year = "2022",

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doi = "10.1038/s41467-022-31367-4",

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T1 - Light-intensity-dependent photoresponse time of organic photodetectors and its molecular origin

AU - Labanti, Chiara

AU - Wu, Jiaying

AU - Shin, Jisoo

AU - Limbu, Saurav

AU - Yun, Sungyoung

AU - Fang, Feifei

AU - Park, Song Yi

AU - Heo, Chul Joon

AU - Lim, Younhee

AU - Choi, Taejin

AU - Kim, Hyeong Ju

AU - Hong, Hyerim

AU - Choi, Byoungki

AU - Park, Kyung Bae

AU - Durrant, James R.

AU - Kim, Ji Seon

N1 - Funding Information: We thank Samsung Electronics for the project funding and the UK EPSRC for ATIP program grant (EP/T028513/1) and Center for Doctoral Training in Plastic Electronic Materials (EP/L016702/1). Publisher Copyright: © 2022, The Author(s).

PY - 2022/12

Y1 - 2022/12

N2 - Organic photodetectors (OPDs) exhibit superior spectral responses but slower photoresponse times compared to inorganic counterparts. Herein, we study the light-intensity-dependent OPD photoresponse time with two small-molecule donors (planar MPTA or twisted NP-SA) co-evaporated with C60 acceptors. MPTA:C60 exhibits the fastest response time at high-light intensities (>0.5 mW/cm2), attributed to its planar structure favoring strong intermolecular interactions. However, this blend exhibits the slowest response at low-light intensities, which is correlated with biphasic photocurrent transients indicative of the presence of a low density of deep trap states. Optical, structural, and energetical analyses indicate that MPTA molecular packing is strongly disrupted by C60, resulting in a larger (370 meV) HOMO level shift. This results in greater energetic inhomogeneity including possible MPTA-C60 adduct formation, leading to deep trap states which limit the low-light photoresponse time. This work provides important insights into the small molecule design rules critical for low charge-trapping and high-speed OPD applications.

AB - Organic photodetectors (OPDs) exhibit superior spectral responses but slower photoresponse times compared to inorganic counterparts. Herein, we study the light-intensity-dependent OPD photoresponse time with two small-molecule donors (planar MPTA or twisted NP-SA) co-evaporated with C60 acceptors. MPTA:C60 exhibits the fastest response time at high-light intensities (>0.5 mW/cm2), attributed to its planar structure favoring strong intermolecular interactions. However, this blend exhibits the slowest response at low-light intensities, which is correlated with biphasic photocurrent transients indicative of the presence of a low density of deep trap states. Optical, structural, and energetical analyses indicate that MPTA molecular packing is strongly disrupted by C60, resulting in a larger (370 meV) HOMO level shift. This results in greater energetic inhomogeneity including possible MPTA-C60 adduct formation, leading to deep trap states which limit the low-light photoresponse time. This work provides important insights into the small molecule design rules critical for low charge-trapping and high-speed OPD applications.

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Light-intensity-dependent photoresponse time of organic photodetectors and its molecular origin

Abstract

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