Bulk ion-clustering and surface ion-layering effects on work function of self-compensated charged-doped polymer semiconductors

Abstract

Self-compensated hole- and electron-doped polyelectrolytes can afford 0.1 eV tuning steps in work function of charge injection/collection layers through the tethered anions. These material systems are further immune to ‘dopant’ migration.

Suppression of Ionic Doping by Molecular Dopants in Conjugated Polymers for Improving Specificity and Sensitivity in Biosensing Applications

“…Crystallites of PT-COOH are seen in microscopic images in Figures f (confocal) and S3b (optical). PT-COOH shows self-doping effects from carboxylic acid groups. − The negatively charged carboxylate stabilizes positive charges on the backbone by electrostatic interactions (Figure f), enabling higher hole carrier concentrations on the polymer backbone . The self-doping effects in PT-COOH are supported by our prior studies , of a large intrinsic hole concentration ( p 0 ) of 1.06 × 10 19 cm –3 for PT-COOH, compared to that of the P3HT film (2.4 × 10 17 cm –3 ).…”

“…20−22 The negatively charged carboxylate stabilizes positive charges on the backbone by electrostatic interactions (Figure 1f), enabling higher hole carrier concentrations on the polymer backbone. 22 The self-doping effects in PT-COOH are supported by our prior studies 23,30 of a large intrinsic hole concentration (p 0 ) of 1.06 × 10 19 cm −3 for PT-COOH, compared to that of the P3HT film (2.4 × 10 17 cm −3 ). This result also corresponds to a higher drain current in the organic field-effect transistor (OFET) device structure with PT-COOH (∼mA) as a semiconductor than with P3HT (∼μA) (Figure S4).…”

“…Such functionality is much more difficult to incorporate into PEDOT:PSS. However, PT-COOH itself is complicated by additional interactions between PT backbones and COOH side chains that lead to self-doping. − Hole carriers are injected into the main backbone of the π-conjugated system that is compensated by proton reduction or transfer occurring at/from the acidic COOH moiety, resulting in the formation of a carboxylate moiety that serves as the oppositely charged counterion. We investigated this critical role of COOH groups in PT-COOH by comparing it with P3HT.…”

Double-type-I charge-injection heterostructure for quantum-dot light-emitting diodes

“…N5 has the same polyfluorene semiconductor core and work function as N3, but a higher ion density for improved adhesion to ITO. 24,50 The JVL and Z-J characteristics are shown in Fig. 6c.…”

Nearly 100% Photocrosslinking Efficiency in Ultrahigh Work Function Hole-Doped Conjugated Polymers Using Bis(fluorophenyl azide) Additives

“…Materials. (3E,5E)-3,5-Bis(4-azido-3,5-difluoro-2,6-diisopropylbenzylidene)-1,1-dimethyl-4-oxopiperidin-1-ium trifluoromethanesulfonate (sFPA82-TfO) was synthesized in-house following Teo et al 25 T w o d i ff e r e n t m o l e c u l a r w e i g h t p o l y ( 9 , 9 -b i s ( 3 -(pentafluoroethanesulfonylimidosulfonyl)propyl)fluorene-2,7-diyl-alt-1,4-phenylene-(m-trifluoromethylphenylimino)-1,4-phenylene) sodium salts (mTFF-C 2 F 5 SIS-Na) were synthesized in-house following Ang et al 32 Their weight-average molecular weights (M w ) are determined by gel permeation chromatography (N,N-dimethylformamide, 0.1 M lithium bromide). The two mTFF-C 2 F 5 SIS-Na have a M w of 80k (PDI, 1.9) and 40k (PDI 1.6), respectively.…”