The ability to laminate and delaminate top metal contacts during the processing and testing of inverted polymer solar cells has led us to uncover the peculiar dependence of their open-circuit voltage (V(oc)) on the annealing sequence. Specifically, thermally annealing inverted polymer solar cells having bulk-heterojunction photoactive layers after top electrode deposition above 100 °C leads to lower V(oc) compared to analogous devices with unannealed photoactive layers or photoactive layers that have been annealed prior to metal electrode deposition. This reduction in V(oc), however, can be reversed when the top electrodes are replaced. This observation is thus a strong indication that such changes in V(oc) with annealing sequence are manifestations of changes at the top electrode-photoactive layer interface, and not structural changes in the bulk of the photoactive layer. Electronic characterization conducted on the photoactive layers and metal contacts after dissection of the polymer solar cells via delamination suggests the reduction of V(oc) on thermal annealing in the presence of the metal top contacts to stem from an interfacial chemical reaction between the photoactive layers and the metal electrodes. This chemically generated interfacial layer is removed upon electrode delamination, effectively reverting the V(oc) to its original value prior to thermal annealing when the top electrodes are replaced.

Download full-text PDF

Source
http://dx.doi.org/10.1021/la202178pDOI Listing

Publication Analysis

Top Keywords

photoactive layers
24
polymer solar
16
solar cells
16
annealing sequence
12
inverted polymer
12
top electrodes
12
open-circuit voltage
8
interfacial chemical
8
chemical reaction
8
metal contacts
8

Similar Publications

Interfacial seed-assisted FAPbI crystallization and phase stabilization enhance the performance of all-air-processed perovskite solar cells.

Dalton Trans

January 2025

State Key Laboratory of Organic Electronics and Information Displays & Institute of Advanced Materials (IAM), School of Materials Science and Engineering, Nanjing University of Posts & Telecommunications, 9 Wenyuan Road, Nanjing 210023, China.

Formamidinium lead triiodide (FAPbI) has received significant attention in the field of perovskite solar cells (PSCs) owing to its excellent optoelectronic properties and high thermal stability. However, the photoactive α-FAPbI perovskites are highly susceptible to degradation into non-perovskite δ-FAPbI phases, especially under humid conditions, which severely diminishes the device performance of FAPbI PSCs. Here, we propose an interfacial seeding strategy for regulating crystallization and stabilizing α-FAPbI perovskites in humid air.

View Article and Find Full Text PDF

Dye-sensitization is a promising strategy to improve the light absorption and photoactivity abilities of wide-bandgap semiconductors, like TiO. For effective water-splitting photoanodes with no sacrificial agents, the electrochemical potential of the dye must exceed the thermodynamic threshold needed for the oxygen evolution reaction. This study investigates two promising organic cyanoacrylic dyes, designed to meet that criterion by means of theoretical calculations.

View Article and Find Full Text PDF

The development of devices capable of storing energy harnessed from photons is on the rise, owing to the increasing global energy demand for smart systems. The majority of reports in this field cover the use of integrated type devices, which houses a separate photovoltaic module and supercapacitor or battery. Herein, we are reporting a photocapacitor with a simple two-electrode design, capable of operating without a conventional electrolyte or metal ions.

View Article and Find Full Text PDF

The ground-state charge generation (GSCG) in photoactive layers determines whether the photogenerated carriers occupy the deep trap energy levels, which, in turn, affects the device performance of organic solar cells (OSCs). In this work, charge-quadrupole electrostatic interactions are modulated to achieve GSCG through a molecular strategy of introducing different numbers of F atom substitutions on the BTA3 side chain. The results show that 8F substitution (BTA3-8F) and 16F substitution (BTA3-16F) lead to different patterns of highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy level changes.

View Article and Find Full Text PDF

Most current highly efficient organic solar cells utilize small molecules like Y6 and its derivatives as electron acceptors in the photoactive layer. In this work, a small molecule acceptor, SC8-IT4F, is developed through outer side chain engineering on the terminal thiophene of a conjugated 6,12-dihydro-dithienoindeno[2,3-d:2',3'-d']-s-indaceno[1,2-b:5,6-b']dithiophene (IDTT) central core. Compared to the reference molecule C8-IT4F, which lacks outer side chains, SC8-IT4F displays notable differences in molecule geometry (as shown by simulations), thermal behavior, single-crystal packing, and film morphology.

View Article and Find Full Text PDF

Want AI Summaries of new PubMed Abstracts delivered to your In-box?

Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!