Alcohol-Soluble Isoindigo Derivative IIDTh-NSB as a Novel Modifier of ZnO in Inverted Polymer Solar Cells

Abstract

Alcohol-soluble isoindigo derivative with thiophene groups and sulfobetaine zwitterions, IIDTh-NSB was applied as a novel modifier of ZnO in inverted polymer solar cells (i-PSCs). When IIDTh-NSB (0.2 mg/mL) was spin-coated on ZnO as an electron transport layer (ETL), power conversion efficiency (PCE) of the PTB7:PCBM based i-PSCs reached 8.88%, which is a 20% improvement of that of 7.40% for the device with the ZnO-only ETL. If ZnO was doped by IIDTh-NSB of 1.0 wt %, the PCE of 8.50% could be achieved in the i-PSCs. Combined measurements of capacitance-voltage characteristics, carrier mobility, and photocurrent density-effective voltage characteristics revealed that incorporating IIDTh-NSB as the modifier of ZnO by coating or doping enhanced the built-in potential, charge carrier density and mobility, exciton dissociation, and charge carrier extraction in the i-PSCs because of the improved interfacial contact between the photoactive layer and ZnO as shown in water contact angle measurements and atomic force microscopy images. Finally, impedance spectroscopy investigation provided strong lines of evidence that incorporating IIDTh-NSB as the modifier of ZnO led to the great enhancement in short-circuit current density and fill factor. Furthermore, all the devices with IIDTh-NSB as a modifier of ZnO presented better stability than the device with ZnO-only. These findings suggest that IIDTh-NSB is an effective and competitive material for modification of ZnO in the i-PSCs.

Insights into Working Mechanism of Alkali Metal Fluorides as Dopants of ZnO Films in Inverted Polymer Solar Cells

“…More than 30 devices for all device configurations were measured to ensure the validity and repeatability of data. Device 1 displays an average PCE of 7.31% comparable to the reported values by others under similar conditions . When the ZnO was doped by AMF, simultaneous improvements in V OC , J SC , and FF have been observed in the i-PSCs.…”

“…Polymer solar cells (PSCs) have been widely investigated thanks to some particular features, for example, low cost, light weight, flexibility, solution processing, and the potential for fabricating large-area PSCs. − Power conversion efficiency (PCE) has been quickly boosted via synthesis of original photoactive materials, − modification of interface layers, − morphology control of active layers, , and design of new device structures. , So far, a champion PCE value of 14.62% has been achieved in the ternary inverted PSCs (i-PSCs) . Recently, i-PSCs have been developed rapidly due to their higher PCE and better device stability than conventional PSCs .…”

A New Alcohol‐Soluble Polymer PFN‐ID as Cathode Interlayer to Optimize Performance of Conventional Polymer Solar Cells by Increasing Electron Mobility

“…The electron-deficient ID is an ideal unit for building D-A molecules and n-type semiconductors, suggesting that ID is an excellent central part of the development of CILs materials. [34,35] PFN-ID can be prepared at low temperature (105 °C) and is soluble in methanol solution after the addition of 0.3% acetic acid, which holds promise for a low-cost noninterfacial mixed solution method for the preparation of PSCs. The chemical and physical properties of the photovoltaic devices demonstrated that the incorporated PFN-ID can effectively inhibit charge recombination, decrease the WF of the cathode, and form an excellent ohmic contact at the interface.…”

Surfactant-Encapsulated Polyoxometalate Complex as a Cathode Interlayer for Nonfullerene Polymer Solar Cells

“…In order to study the exciton dissociation and charge collection properties of the devices with different cathode, we selectively investigated the J ph -V eff characteristics of the PM6:Y6 based NF-PSCs. 51,54 J ph presents the difference between photocurrent under the light (Figure 2a) and in the dark (Figure S7). As shown in Figure 3a, the J ph reached saturated photocurrent (J ph,sat ) when the V eff approached 2 V. J ph /J ph,sat ratios could estimate the probabilities of exciton dissociation and charge carrier collection.…”

“…46,47 Advantages of the TOASiW 12 over other organic CIL materials for large-area production of the PSCs are evident because of its low-cost (< $1/g), simple, green (solvents: alcohol and water) and high-yield (> 90%) synthetic procedures. [48][49][50] Compared to ZnO, 51 it does not require thermal annealing and has better adhesion and compatibility with the active layer due to introducing sixteen flexible alkyl chains. In addition, TOASiW 12 is more environmentally friendly than ZrAcAc.…”