Effect of hydrogen chloride etching on carrier recombination processes of indium phosphide nanowires

et al. 2020

Molecules

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Y6 is a new type of non-fullerene acceptor, which has led to power conversion efficiencies of single-junction polymer solar cells over 17% when combined with a careful choice of polymeric donors. However, the excited state characteristics of Y6, which is closely correlated with its opto-electronic applications, are not clear yet. In this work, we studied the excited state properties of the Y6 solution and Y6 film, by using steady-state and time-resolved spectroscopies as well as time-dependent density functional theory (TD-DFT) calculations. UV-Vis absorption and fluorescence simulation, natural transition orbitals (NTOs) and hole-electron distribution analysis of Y6 solution were performed for understanding the excitation properties of Y6 by using TD-DFT calculations. The lifetimes of the lowest singlet excited state in Y6 solution and film were estimated to be 0.98 and 0.8 ns, respectively. Combining the exciton lifetime and photoluminescence (PL) quantum yield, the intrinsic radiative decay lifetimes of Y6 in the solution and film were estimated, which were 1.3 and 10.5 ns for the Y6 solution and film, respectively. Long exciton lifetime (~0.8 ns) and intrinsic radiative decay lifetime (~10.5 ns) of Y6 film enable Y6 to be a good acceptor material for the application of polymer solar cells.

Section: Methodsmentioning

confidence: 99%

An Insight into the Excitation States of Small Molecular Semiconductor Y6

Zou

et al. 2020

Molecules

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“…2.4 Time-resolved photoluminescence (TRPL) and absolute photoluminescence quantum yield (PLQY) measurements TRPL was measured in a setup described in the previous works. 27,28 A fs pulsed laser (Tsunami, Spectra-Physical) with wavelength of 800 nm, pulse duration of $100 fs and repetitive rate of 80 MHz, was employed as the laser source. The frequency-doubled laser (400 nm) was employed as exciting light.…”

Section: Transient Absorption (Ta) Measurementsmentioning

confidence: 99%

Ground- and excited-state characteristics in photovoltaic polymer N2200

Zou

et al. 2021

RSC Adv.

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“…Time resolved photoluminescence (TRPL) of the pure polymer film and the blended films were measured using a streak camera system described in previous works [26,27]. A fs pulsed laser (Spectra-Physics, Tsunami, Irvine, CA, USA) emitting at 800 nm with 81 MHz and pulse duration of ~100 fs was employed as the light source of the system.…”

Section: Ta and Time-resolved Photoluminescence (Trpl) Measurementsmentioning

confidence: 99%

Understanding of Photophysical Processes in DIO Additive-Treated PTB7:PC71BM Solar Cells

et al. 2021

Crystals

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1,8-diiodooctane (DIO) additive is an important method for optimizing the morphology and device performance of polythieno[3,4-b]-thiophene-co-benzodithiophene (PTB7)-based polymer solar cells. However, the effect of DIO additive on charge photogeneration dynamics of PTB7-based polymer solar cells is still poorly understood. In this work, the effect of DIO additive on the carrier photogeneration dynamics, as well as device performance of PTB7: [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM) solar cells was studied. Bias-dependent photoluminescence (PL) experiments of a neat PTB7 device show that the exciton cannot be dissociated by the electric field in the device within the operating voltage range, but it can be effectively dissociated by the high electric field. PL and time-resolved PL studies show that DIO additive reduces the phase size of PTB7 in the blend film, resulting in an increased exciton dissociation efficiency. The carrier recombination processes were studied by transient absorption, which shows geminate carrier recombination was suppressed in the DIO-treated PTB7:PC71BM device in ultrafast time scale. The increased exciton dissociation efficiency and suppressed carrier recombination in ultrafast time scale play an important role for DIO-treated PTB7:PC71BM solar cells to attain a higher power conversion efficiency.