Understanding the dopant induced effects on SFX-MeOTAD for perovskite solar cells: a spectroscopic and computational investigation

Abstract

SFX-MeOTAD [2,2′,7,7′-Tetrakis(N,N-di(4-methoxyphenyl)amino)-spiro-(fluorene-9,9′-xanthene)] (also known as X60) has emerged as a cost-effective alternative to the ubiquitous, but excessively-expensive, spiro-MeOTAD hole transport material (HTM) in perovskite solar cells. Using its pre-oxidised dicationic...

Non-nucleophilic electrolyte with non-fluorinated hybrid solvents for long-life magnesium metal batteries

“…S12 (ESI†), respectively. The decomposition of both DME and DME-THF electrolytes induced similar species on the top surface of the Mg anode (0 s, before sputtering), including MgF 2 (∼685.2 eV), 58 C–F (∼688.2 eV, 292.7 eV), 9,59 MgSO 3 (167.0 eV, 168.2 eV), 60 MgS x (164.1 eV, 165.3 eV, 162.0 eV, 163.2 eV), 60,61 C–H/C–C (284.8 eV), 40 C–O (286.6 eV, 532.5 eV), 40 CO (288.0 eV) 62 and MgCO 3 (290.0 eV). 63 MgF 2 originated from the decomposition of TFSI − , 40 while C–F groups originated from either the decomposition or adsorption of TFSI − anions.…”

Vapor Phase Infiltration Improves Thermal Stability of Organic Layers in Perovskite Solar Cells

“…The first is caused by dopants. Spiro-OMeTAD requires the use of dopant additives to improve its conductivity through the formation of oxidized spiro­[TFSI] 2 . − Although this is beneficial for the initial performance of the devices, spiro­[TFSI] 2 rapidly reacts with iodide ions that migrate from the perovskite layer and reduces back to spiro-OMeTAD, which decreases the conductivity of the layer over time . In the second pathway, the spiro-OMeTAD layer allows the migration of gold ions from the back contact into the perovskite layer, which has been suggested as another route to irreversible degradation of PSCs .…”