High-efficiency polymer photovoltaic cells using a solution-processable insulating interfacial nanolayer: the role of the insulating nanolayer

Abstract

We employed a low-cost solution-processed ultrathin insulating polymeric layer of poly(4-hydroxystyrene) (PHS), with a high glass transition temperature (T g $ 185 C), as an interfacial layer between the polymer:fullerene photoactive layer and the Al negative electrode for enhancing device power conversion efficiency (PCE) of polymer bulk-heterojunction photovoltaic cells and investigated the roles of the interfacial nanolayer by ultraviolet photoemission spectroscopy and capacitance-voltage measurement. The thin polymeric layer forms a dipole layer and causes the vacuum level of the adjacent negative electrode to shift upward, which resulted in an increase of the built-in potential. As a result, the open-circuit voltage and PCE of the device using a PHS nanolayer were remarkably improved. We finally achieved a very high PCE of 6.5% with the PHS/Al negative electrode which is even much better than that of the device using an Al electrode (5.0%). The solutionprocessed inexpensive PHS layer with a high T g can be an attractive alternative to conventional vacuum-deposited low-work-function metal and insulating metal fluoride interfacial layers.

Self‐Doped Conducting Polymer as a Hole‐Extraction Layer in Organic–Inorganic Hybrid Perovskite Solar Cells

“…Moreover, PSS‐ g ‐PANI:PFI shows the higher WF and the deeper surface energy state compared to PEDOT:PSS and PSS‐ g ‐PANI. As a result, the energy offset between the surface energy state of PSS‐ g ‐PANI:PFI and the VBM of MAPbI 3 (–5.43 eV) is perfectly eliminated and forms an ohmic contact at the interface . Therefore, we expect that the V bi and corresponding V oc in the device approach their maximum values because the potential loss of photogenerated charge is minimized at the interface between PSS‐ g ‐PANI:PFI and MAPbI 3 .…”

“…In the first few papers reporting SP‐PHJ PrSCs, they were based on the PEDOT:PSS HTM because PEDOT:PSS is one of the most commonly used HTMs for organic photovoltaicsand organic light‐emitting diodes (OLEDs) . However, work function (WF) of PEDOT:PSS (≈4.9–5.2 eV) is highly dependent on the ratio of the polymeric acid, PSS relative to PEDOT and therefore may not be sufficiently high to perfectly match the valence band maxima (VBM) of perovskite materials (e.g., –5.43 eV for methylammonium lead iodide (MAPbI 3 )) for ohmic contact and consequential efficient charge extraction . Moreover, PEDOT:PSS is dispersed with a large particle size (≈60 nm) in solution; it precipitates slowly from the solution during storage and is difficult to redisperse from the aggregated solid.…”

Enhanced performance of solution-processed solar cells based on porphyrin small molecules with a diketopyrrolopyrrole acceptor unit and a pyridine additive

“…2c. 8,[42][43][44] The device performance was rstly explored by blending Por-2 with PC 61 BM at different ratios ranging from 2 : 1 to 1 : 1.5 in chlorobenzene (CB)/1,2-dichlorobenzene (DCB) (Table S1 and Fig. S3 †).…”

Organic Photodetectors in Analytical Applications

“…The immunoassay was employed to detect recombinant human thyroid stimulating hormone (rhTSH), a marker for diagnosis of thyroid cancer. In addition to using PCDTBT (instead of P3HT), which is known to lead to a higher short circuit current [48], the OPD was further optimized by changing the thickness of PEDOT:PSS and the active layer. Hence, a low LOD was obtained with the OPD monitoring the ~425 nm CL signal due to the interaction between anti-rhTSH monoclonal antibody, rhTSH antigen, and a biotinylated secondary antibody complex together with HRP.…”