Structural spectral response tuning in organic deep ultraviolet photodetectors

Abstract We demonstrated novel organic deep ultraviolet photodetectors with structural spectral response tuning through bulk heterojunctions (HJs) and mixed planar-bulk HJs (PBHJs), respectively. TAPC and BAlq were utilized as the electron donor and acceptor, as well as polymer PEDOT:PSS was present as the transparent anode. The mixed PBHJs and bulk HJs reveal extremely low dark current of 3.35 × 10 −8 and 2.94 × 10 −8  A/cm 2 , and high photocurrent of 3.01 × 10 −5 and 9.55 × 10 −5  A/cm 2 at −10 V under 260 nm light illumination with an intensity of 0.91 mW/cm 2 , respectively. A peak response of 33.6 mA/W at ∼260 nm and a detectivity of 3.24 × 10 11  cm Hz 1/2  W −1 are achieved in the mixed PBHJs. The bulk HJs exhibit a maximum response of 100.8 mA/W at ∼280 nm and a detectivity of 1.04 × 10 12  cm Hz 1/2  W −1 . The photophysics involved in structural spectral response tuning are also discussed in detail.