A regioregular donor–acceptor copolymer allowing a high gain–bandwidth product to be obtained in photomultiplication-type organic photodiodes

Kim, Juhee; So, Chan; Kang, Mingyun; Sim, Kyu Min; Lim, Bogyu; Chung, Dae Sung

doi:10.1039/d0mh01588a

Cited by 32 publications

(45 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Considering DAB_c molecules are spatially isolated (content is 1% by weight) and do not form percolation pathways for electrons, the trapped electrons are stable enough to induce Schottky barrier thinning followed by hole injection under a reverse bias (Figure 1c). [30][31][32][33][34][35][36] This mechanism is analogous to that of photomultiplicationtype OPDs comprising a p-type polymer and a small number of n-type small molecules. To confirm the first requirement we conducted ultraviolet photoelectron spectroscopy (UPS) analyses with and without continuous illumination using a UV laser (375 nm) at the 10A2 beamline of the Pohang Accelerator Laboratory (PAL, Republic of Korea).…”

Section: Optoelectrical Properties Of Dabmentioning

confidence: 99%

A Molecular‐Switch‐Embedded Organic Photodiode for Capturing Images against Strong Backlight

Kang

Hassan

et al. 2022

Advanced Materials

Self Cite

View full text Add to dashboard Cite

When the intensity of the incident light increases, the photocurrents of organic photodiodes (OPDs) exhibit relatively early saturation, due to which OPDs cannot easily detect objects against strong backlights, such as sunlight. In this study, this problem is addressed by introducing a light‐intensity‐dependent transition of the operation mode, such that the operation mode of the OPD autonomously changes to overcome early photocurrent saturation as the incident light intensity passes the threshold intensity. The photoactive layer is doped with a strategically designed and synthesized molecular switch, 1,2‐bis‐(2‐methyl‐5‐(4‐cyanobiphenyl)‐3‐thienyl)tetrafluorobenzene (DAB). The proposed OPD exhibits a typical OPD performance with an external quantum efficiency (EQE) of <100% and a photomultiplication behavior with an EQE of >100% under low‐intensity and high‐intensity light illuminations, respectively, thereby resulting in an extension of the photoresponse linearity to a light intensity of 434 mW cm−2. This unique and reversible transition of the operation mode can be explained by the unbalanced quantum yield of photocyclization/photocycloreversion of the molecular switch. The details of the operation mechanism are discussed in conjunction with various photophysical analyses. Furthermore, they establish a prototype image sensor with an array of molecular‐switch‐embedded OPD pixels to demonstrate their extremely high sensitivity against strong light illumination.

show abstract

Section: Optoelectrical Properties Of Dabmentioning

confidence: 99%

A Molecular‐Switch‐Embedded Organic Photodiode for Capturing Images against Strong Backlight

Kang

Hassan

et al. 2022

Advanced Materials

Self Cite

View full text Add to dashboard Cite

show abstract

“…Photodetectors have attracted wide interest due to their huge potential in different application fields, such as image sensing, fluorescence microscopy, and defense applications. − Broad-band response organic photodetectors can be commonly achieved by employing one wide bandgap material with one narrow bandgap material as the active layers, also working under a photodiode model with an external quantum efficiency (EQE) less than 100%. − There are huge challenges to achieve narrow-band-response organic photodetectors because of the relatively broad photon harvesting range of organic materials, especially for photomultiplication organic photodetectors (PM-OPDs) with EQEs larger than 100%. − The PM-OPDs can be realized through charge-tunneling injection induced by interfacial traps, and the spectral response of PM-OPDs is mainly determined by the trapped-charge distribution close to the opposite charge injection electrode, which provides more possibilities to adjust the spectral response range of PM-OPDs by interfacial engineering or a light management strategy. − PM-OPDs can work well under reverse and forward applied voltage by replacing PEDOT:PSS with PFN as the anode interfacial layer, exhibiting a broad-band response from 350–800 nm with one narrow-band-response peak at 800 nm with a full-width at half-maximum (fwhm) of 40 nm . The PM-OPDs possessing narrow-band and broad-band photodetection capability were realized by using 16 nm Al thin film as the top semitransparent electrode .…”

mentioning

confidence: 99%

Ultra-Narrow-Band NIR Photomultiplication Organic Photodetectors Based on Charge Injection Narrowing

Liu

Wang

Zhao

et al. 2021

J. Phys. Chem. Lett.

103

View full text Add to dashboard Cite

Ultra-narrowband NIR photomultiplication organic photodetectors (PM-OPDs) were realized in ITO/PEDOT:PSS/active layers/Al based on the interfacial-traps induced charge injection narrowing (CIN) concept. The rather less Bod Ethex-Hex (BEH) is imbedded in polymer donor matrix to form some isolated electron traps. The trapped electrons in BEH closing Al electrode will force interfacial band-bending for hole-tunneling-injection, resulting in the photomultiplication. The PM-OPDs with P3HT:BEH as active layers exhibit narrow response peak at 850 nm with full width at half-maximum (FWHM) of 27 nm, as well as a rather weak response from 650 m to 800 nm. The rejection ratios (RRs) are 11 at EQE 855 nm /EQE 700 nm and 10 at EQE 855 nm /EQE 750 nm , respectively. The EQE of 29,700% at 850 nm was achieved in the PM-OPDs by incorporating 0.02 wt% F 6 TCNNQ under -13 V bias. An EQE of 15,300% at 850 nm was achieved in the ternary PM-OPDs at -13 V bias, with the markedly enhanced RRs of 44 at EQE 855 nm /EQE 700 nm and 30 at EQE 855 nm /EQE 750 nm . This work provides a smart strategy to achieve highly efficient ultra-narrowband NIR PM-OPDs by adjusting trapped-electron-distribution near hole injection electrode and molecular arrangement for enhancing hole mobility in active layers.

show abstract

“…G–B products of previous PM‐OPDs where both measurements of the gain and bandwidth were conducted under the same illumination condition are summarized in Table 2 and one can find out that such a high G–B product has not been reported. [ 3,10,41,42 ] The G–B product of the proposed PM‐OPD is ≈50 times higher than the previous record.…”

Section: Resultsmentioning

confidence: 68%

Interfacial Electrostatic‐Interaction‐Enhanced Photomultiplication for Ultrahigh External Quantum Efficiency of Organic Photodiodes

et al. 2021

Self Cite

View full text Add to dashboard Cite

A photomultiplication-type organic photodiode (PM-OPD), where an electric double layer (EDL) is strategically embedded, is demonstrated, with an exceptionally high external quantum efficiency (EQE) of 2 210 000%, responsivity of 11 200 A W −1 , specific detectivity of 2.11 × 10 14 Jones, and gain-bandwidth product of 1.92 × 10 7 Hz, as well as high reproducibility. A polymer electrolyte, poly(9,9-bis(3′-(N,N-dimethyl)-N-ethylammoinium-propyl-2,7-fluorene)-alt-2,7-(9,9-dioctylfluorene))dibromide is employed as a work-function-modifying layer of indium tin oxide (ITO) to construct an EDL-embedded Schottky junction with p-type polymer semiconductor, poly(3-hexylthiophene-diyl), resulting in not only advantageous tuning of the work function of ITO but also an enhancement of the electron-trapping efficiency due to electrostatic interaction between exposed cations and trapped electrons within isolated acceptor domains. The effects of the EDL on the energetics of the trapped electron states and thus on the gain generation mechanism are confirmed by numerical simulations based on the drift-diffusion approximation of charge carriers. The feasibility of the fabricated high-EQE PM-OPD especially for weak light detection is demonstrated via a pixelated prototype image sensor. It is believed that this new OPD platform opens up the possibility for the ultrahigh-sensitivity organic image sensors, while maintaining the advantageous properties of organics.

show abstract

A regioregular donor–acceptor copolymer allowing a high gain–bandwidth product to be obtained in photomultiplication-type organic photodiodes

Abstract: A high gain-bandwidth product of photomultiplication-type organic photodiode is limited. We show that newly designed regioregular polymer enables a highly oriented face-on structure with a low trap density, leading to...

Cited by 32 publications

References 33 publications

A Molecular‐Switch‐Embedded Organic Photodiode for Capturing Images against Strong Backlight

A Molecular‐Switch‐Embedded Organic Photodiode for Capturing Images against Strong Backlight

Ultra-Narrow-Band NIR Photomultiplication Organic Photodetectors Based on Charge Injection Narrowing

Interfacial Electrostatic‐Interaction‐Enhanced Photomultiplication for Ultrahigh External Quantum Efficiency of Organic Photodiodes

Contact Info

Product

Resources

About