PTCDI-Ph Molecular Layer Stack-Based Highly Crystalline Microneedles As Single-Component Efficient Photodetector

Abstract

Phenyl-substituted perylene diimide derivative N,N-diphenyl perylene tetracarboxylic diimide (PTCDI-Ph) has been used as a single-component organic material to fabricate an efficient photodetector. PTCDI-Ph grows as one-dimensional microneedles composed of stacks of molecular layers with substrate temperatures. Such structure formation is due to the lower diffusion activation energy (0.21 eV) of the molecules along the length of the microneedles than along the width (0.34 eV). The photoresponse from these structures has been significantly enhanced because of the reduction of traps as a result of enhanced diffusion of the molecules at higher substrate temperatures. The observed photosensitivity and photoresponse time of the devices fabricated with the films grown at a 140 °C substrate temperature are 333 and 0.12 s, respectively. The decrement of the traps due to the defect states with the increment of substrate temperature is confirmed by the photoluminescence (PL) and time-resolved photoluminescence spectra (TRPL). The photocurrent covers the visible-light spectrum, indicating that the PTCDI-Ph microneedle is a promising candidate for the fabrication of single-material-based photodetectors.

Spectrally Selective Full-Color Single-Component Organic Photodetectors Based on Donor-Acceptor Conjugated Molecules

“…Therefore, a popular approach is to reduce the dark current by increasing the photoactive layer thickness to achieve a higher shunt resistance, although this faces a trade-off between high values of EQE, R , response speed, D* , and low J dark values. Although the specific detectivity values turned out to be small, they are not inferior, and sometimes even superior to those for other recently published single-component photodetectors [ 17 , 18 , 19 , 20 ].…”

“…Recently, much attention has been paid to single-component solar cells based on donor-acceptor materials [ 15 , 16 ]. At the same time, single-component organic photodetectors have far less studied, as follows from articles [ 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 ]. Single-component organic photodetectors benefit primarily from their simplicity, which is especially important for biological applications.…”