Interface engineered, high photo-response of self-powered photodetector and solar cell based on PEDOT:PSS-silicon hybrid heterojunction

Over the years, organic material based photodetectors have been explored with a great success. However, optoelectronic applications of organic-inorganic hybrid photodetectors have gained the significant attention of the scientific community in the recent years due to their higher performance and lower fabrication cost. Here, the hybrid heterojunction model based on silicon (Si) and a conjugate organic polymer, poly (3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) is explored as self-biased, broadband and high-speed photodetectors, which are least explored when compared to its solar cell counterparts. Thus, photovoltaic (PV) as well as self-biased broadband light detection capabilities, enhanced via employing PEDOT:PSS/Si hybrid heterojunction over optimized surface micro-texturing of Si surface, are explored. The hybrid device ‘Ag/PEDOT:PSS/n-Si/In:Ga’ exhibited an excellent PV performance with maximum efficiency of 11.57 % under standard test conditions, contributed by enhanced light trapping (Reflectance: <9.50 % in 400–1100 nm), passivation of Si surface by PEDOT:PSS layer (carrier lifetime: >64.00 µs) and excellent PEDOT:PSS/n-Si (micro-textured) interface. The photo-response of the proposed hybrid photodetector was analysed corresponding to 3 different light sources (355 nm, 455 nm and 860 nm) with varying power and voltage. The proposed photodetector also showed promising response; e.g. responsivity of 527.5 mA/W, detectivity of 2.85 × 10 11 Jones, low noise equivalent power (NEP) of 2.58 pW/Hz 1/2 and response time as ∼60 ms under 0 V bias voltage corresponding to 455 nm light irradiation. Additionally, the hybrid photodetector also showed a reasonable response to the other 2 light sources (355 nm and 860 nm). Thus, the results indicate the tremendous possibility and scope of using hybrid PEDOT:PSS/n-Si heterojunction based devices for optical signal detection in broad spectral range apart from solar cell applications. • Optical signal detection capability of hybrid PEDOT:PSS-Si devices is least explored. • Both photodetection and solar cell properties studied in the simplest device design. • Self-powered, broad-band photodetection, and highly efficient PV applications shown. • Surface, reflectance, passivation, junction and PV properties investigated achieving the best PCE of > 11.5 %. • Photodetection with excellent stability, repeatability and high figures of merit achieved.