Impact of P3HT Regioregularity and Molecular Weight on the Efficiency and Stability of Perovskite Solar Cells

Abstract

The commercialization of perovskite solar cells (PSCs) has seen an important limitation in the instability that afflicts the hole-transporting layer (HTL), namely, spiro-OMeTAD, used in high-efficiency devices. The latter is, in turn, relatively expensive, undermining the sustainability of the device. Its replacement with polymeric scaffolds, such as poly(3hexylthiophene) (P3HT), will solve these issues. In this work, we adopted various sustainable synthetic methods to obtain four different homemade P3HTs with different molecular weights (MWs) and regioregularities (RRs), leading to different structural properties. They are implemented as HTLs in PSCs, and the effect of their properties on the efficiency and thermal stability of devices is thoroughly discussed. The highest efficiency is obtained with the highest MW and low-RR polymer (17.6%) owing to the more sustainable approach, but a very promising value is also reached with a lower-MW but fully regioregular polymer (15%). Finally, large-area devices with an efficiency of 16.7%, fabricated with a high-MW P3HT, show more than 1000 h (T80 = 1108 h) of stability under accelerated thermal stress tests (85 °C) out of glovebox while keeping over 85% of the initial efficiency of an unencapsulated device after more than 3000 min under continuous light soaking (AM 1.5G).

Reducing Losses in Perovskite Large Area Solar Technology: Laser Design Optimization for Highly Efficient Modules and Minipanels

“…TiO 2 paste (30NR‐D) was diluted in anhydrous ethanol (1:6 w/w ratio) and deposited by spin‐coating method at 4000 rpm with a ramp of 2000 rpm for 20 s, then substrates were annealed using following program: annealing program from room temperature to 120 °C for 5 min and remain 5 min, 120 to 325 °C for15 min and stay 5 min, 325 to 375 °C for 5 min and stay 5 min, 375 to 480 °C for 5 min and remain 30 min previously reported program. [ 30 ] Li‐salt treatment was performed on the mesoporous layer by deposition of (34.8 × 10 −3 m ) solution bis(trifluoromethane)sulfonimide lithium salt in acetonitrile via spin‐coating at 2000 rpm for 10 s and sintering step at 500 °C for 45 min and kept the temperature at 150 °C, then immediately substrate the substrates immediately were transferred to the glove box before perovskite deposition to prevent of absorbing any water on the surface.…”

Improved Efficiency of Perovskite Solar Cells with Low‐Temperature‐Processed Carbon by Introduction of a Doping‐Free Polymeric Hole Conductor

“…Recently, P3HT with four difference molecular weights ( M Ws ) and regioregularities (RRs) synthesis (19 kDa/95%, 194 kDa/100%, 223 kDa/79%, and 338 kDa/76%, respectively) were investigated as HTMs in PSCs. Polymers with the highest M W and lowest RR polymer increased the PCE to 17.6%, maintaining over 85% of its original efficiency at 85 °C (RH: ≈70%) for over 1000 h. [ 51 ] To date, the highest efficiency obtained in PSCs with P3HT as HTMs of 24.6% was achieved by incorporation of gallium(III) acetylacetonate Ga(acac) 3 into P3HT as HTMs, leading to effective interfacial passivation and superior stability for 2000 h at room temperature (RH ≈85%). [ 41 ]…”

Polymer Hole Transport Materials for Perovskite Solar Cells via Buchwald–Hartwig Amination

“…The variation in PCE of the FlAn reaction series was within standard deviation, suggesting that differences in device parameters between the six HTMs are due to the distinct chemical identities of the HTMs rather than the M w and PDI. In PSCs, variation of the M w , M n , and PDI has been shown to primarily impact device performance through both the increased conductivity and hole mobility of high M n polymers and more uniform polymers films from a smaller PDI. ,, The polymers presented possessed similar M n , indicating minimal variation in electrical properties. Thus, the minimal difference in device performance between the FlAn reaction time series is likely attributable to changes in the PDI.…”