Marked improvement in the stability of small molecule organic photovoltaics by interfacial modification using self-assembled monolayers to prevent indium diffusion into the active layer

The damaging effects of the acidity in PEDOT:PSS on semiconductor device performance and solutions based on non-acidic alternatives

“…28 In another approach, there have been attempts to coat the ITO with a self-assembled monolayer (SAM) to prevent etching and subsequent migration of indium into the hole transport and active layers. In fact, Tai et al 29 showed that even acidic SAMs such as terephthalic acid and derivatives with four and six carboxylic acid groups ( Fig. 3), could be placed in the interface between ITO and PEDOT:PSS to suppress the migration of indium.…”

“…3 Structures of SAMs used as blocking layers to prevent degradation of ITO from an adjacent PEDOT:PSS layer. [29][30][31] Metal oxides are well known to be used as hole injection layers (see section 4.1: Solution-processed metal oxides/metal complexes). However, such materials have also been used in a bilayer with PEDOT:PSS to prevent acid-induced degradation of ITO.…”

Construction of Interface Dipoles by Surface Doping and Their Role in the Open Circuit Voltage in Polymer Solar Cells

“…19,20 For example, unencapsulated P3HT:PCBM solar cell devices with PEDOT:PSS show a rapid decay of the short circuit current. 21 In order to solve this problem, various approaches have been reported, including introducing another buffer layer beneath PEDOT:PSS, [22][23][24] posttreatment of PEDOT:PSS, 25,26 doping PEDOT:PSS, 27,28 or replacing PEDOT:PSS. 29,30 The contact between the electrode and the active layer in PSCs is of essential importance, and the proper WF of the electrode is expected to form ohmic contacts in the device to reduce the energy barrier of the interface.…”

Unexpected Equilibrium Ionic Distribution in Cyanine/C60 Heterojunctions

“…In the p–n junction, charge transfer across the interface and the resulting depletion zones lead to large vacuum level shifts (band bending). Vacuum level shifts can also be the result of dipoles, orientation of organic molecules at interfaces or the diffusion of organic and inorganic compounds across interfaces . Moreover, p–n junctions can also be obtained by in situ electrochemical doping.…”