Co-localized crosstalk-free multiband organic photodetectors for wearable optoelectronics
- 주제(키워드) organic photodetector , wearable application
- 발행기관 아주대학교 일반대학원
- 지도교수 박성준
- 발행년도 2026
- 학위수여년월 2026. 8
- 학위명 석사
- 학과 및 전공 일반대학원 지능형반도체공학과
- 실제URI http://www.dcollection.net/handler/ajou/000000036639
- 본문언어 영어
- 저작권 아주대학교 논문은 저작권에 의해 보호받습니다.
초록/요약
Multiband organic photodetectors （OPDs） offer a compact route to multifunctional wearable sensing, yet achieving crosstalk-free operation in mechanically compliant stacked architectures is fundamentally limited by trade-offs between spectral selectivity and device efficiency. Here, we report ultra-flexible, co-localized OPDs that mitigate this trade-off and enable crosstalk-free multiband sensing in a skin-conformal platform. By separating spectral selectivity from carrier extraction and employing a composition-optimized photomultiplication effect, the device achieves a crosstalk-free spectral window of 115 nm, together with responsivities of 0.23 A/W at λ = 680 nm for the bottom subcell and 0.44 A/W at λ = 920 nm for the top subcell. Minimizing device thickness enables stable operation under 66% compressive strain and bending radii down to 7 μm, with negligible degradation over 1000 cycles. The devices exhibit detectivities up to 1.12×1011 Jones and bandwidths of 71.7 kHz, enabling motion-robust SpO2 monitoring and dual-channel optical communication over 100 m.
more목차
1. Background 1
1.1 Overview of organic photodetectors (OPDs) 1
1.2 Fundamental working mechanism of OPDs 3
1.3 Figures of merit of OPDs 5
1.3.1 Dark current and noise current 5
1.3.2 External quantum efficiency and responsivity 6
1.3.3 Noise Equivalent Power and Specific Detectivity 6
1.3.4 Response Speed 7
1.3.5 Linear Dynamic Range 7
1.4 Trap-assisted-based photomultiplication effect in OPDs 7
1.5 Recombination-controlled narrowband detection in OPDs 8
1.6 Photoplethysmography and light communication 11
2. Introduction 12
2.1 Limitations of OPDs in multifunctional wearable platforms 12
2.2 Advancements in multiband OPDs 12
2.3 Remaining challenges in stacked OPDs development 13
2.4 Introducing crosstalk-free ultra-flexible stacked OPDs 14
3. Results 15
3.1 Design and optoelectronic characteristics of stacked OPDs 15
3.2 Thickness-dependent optoelectronic characteristics 21
3.3 Composition-induced modulation of trap-assisted tunneling 25
3.4 Mechanical durability of the stacked OPDs 31
3.5 Crosstalk-free motion-robust photoplethysmography and light communication 34
4. Conclusions 39
5. Experimental Section 40
5.1 Materials 40
5.2 Device fabrication 40
5.3 Optical simulation 41
5.4 Electrical and optical measurement 41
5.5 Drift length estimation based on impedance spectroscopy measurements 42
5.6 Trap density analysis based on capacitance–voltage measurements 42
5.7 Mechanical measurements 43
5.8 PPG measurement and SpO2 calculations 43
5.9 Dual-channel light communication 44
6. References 45
