Improvement of fill factor by the utilization of Zn-doped PEDOT:PSS hole-transport layers for p-i-n planar type of perovskite solar cells

Suppressing PEDOT:PSS Doping-Induced Interfacial Recombination Loss in Perovskite Solar Cells

“…One common strategy used to minimize the critical issues mentioned above is to add p-type dopants to the HTL. , The p-type dopants deepen the Fermi level ( E F ) of the HTL and, therefore, can create favorable interfacial energetic alignment, which reduces the energy loss at the interface between the perovskite and HTL. − Importantly, p-type dopants increase the conductivity of the HTL, which can improve the fill factor (FF) of the devices via more-efficient charge extraction. − Despite the success of utilizing dopants in the HTL, some undesirable effects are also introduced with doping. One issue is the device instability caused by dopant dissociation and the hygroscopic nature of some dopants such as lithium­(bis­(trifluoromethanesulfonyl)­imide (LiTFSI). , Another significant effect of doping the HTL is strong recombination loss at the interface.…”

Review on Tailoring PEDOT:PSS Layer for Improved Device Stability of Perovskite Solar Cells

“…Table 1 lists the PCE and long-term stability of PSCs adopting PEDOT:PSS as HTL in previous research work. Generally, modification methods can be classified into three types: doping [61,[78][79][80][81][82][83][84][85][86][87][88][89][90][91][92][93][94], post-treatment [62,[95][96][97] and using bilayer [98][99][100][101][102]. Furthermore, there are some other methods reported to modify the properties of PEDOT:PSS for improving the device stability, such as, using other dopants to replace PSS [56,103], and developing new processing methods of PEDOT:PSS film [104,105], which are discussed in Section 3.…”

“…It has been proved that the conductivity of PEDOT:PSS can be increased from 10 −2 to 10 3 S/cm by doping an organic compound, such as ethylene glycol (EG), dimethyl sulfoxide (DMSO), an ionic liquid, an anionic surfactant, or dimethyl sulfate, into PEDOT:PSS aqueous solution [23][24][25][26][27][28][29]. Besides conductivity, other properties, such as work function, acidity and hydrophilic properties, can also be modified using the doping method [61,[78][79][80][81][82][83][84][85][86][87][88][89][90][91][92][93][94].…”

“…The PSCs with ionic liquid doped PEDOT:PSS film can retain 85% of initial PCE after 35-day storage in air with 60% humidity without encapsulation [93]. Recently, Alishah et al used Zn as an additive in PEDOT:PSS solution to successfully improve the hole mobility and electrical conductivity of PEDOT:PSS film and reduce the perovskite trap density, leading to improved environmental stability with 91% of initial PCE for 168 h [94]. Another effective strategy is to dope PEDOT:PSS with inorganic halometallate to suppress the charge recombination and increase the stability.…”

The versatility of polymers in perovskite solar cells

“…84 Moreover, using Zn-doped PEDOT: PSS as the HTM improved the photovoltaic performance, where the FF increased from 70.00% to 83.00%. 85 Introduction of low-cost and stable conjugated polymer such as poly[(thiophene)- alt -(6,7-difluroro-2-(2-hexyldecyloxy)-quinoxaline)] (PTQ10) as an interfacial layer in planar n–i–p PSC not only improved the active layer quality and suppressed the volatilization of organic cations during the thermal annealing process but also functioned as a hole selective layer. As a result, a champion PCE of 21.20% with a high FF of 81.60% as well as thermal and ambient stability was achieved.…”