Semiconductor measurement technology

Abstract

Materials Characterization by Electrical Methods 7 3.1. U Through MIPR FY76 167600366 (NBS Cost Center 4259560). # Code SP-23, through project order N0016475P070030 administered by Naval Weapons Support Center, Crane, Indiana (NBS Cost Center 4251533).

A Systematic Approach to Solvent Selection Based on Cohesive Energy Densities in a Molecular Bulk Heterojunction System

“…[ 33 ] PC 71 BM shows higher dipole and H-bonding forces than C 60 ; these differences can be attributed to phenyl -methyl butyrate functionalities, which impart a dipole moment and an increase in the H-bonding due to the electronegative O atoms, thus increasing the δ P and δ H parameters relative to C 60 . The Hansen parameters for DPP(TBFu) 2 and PC 71 BM are found to be quite similar, with the biggest differences being that DPP(TBFu) 2 has 1.8 MPa 1/2 larger H-bonding cohesive energy. These results can be rationalized by the presence of two lactam carbonyl groups in DPP(TBFu) 2 , which are known to participate in H-bonding.…”

“…We measured the solubility of DPP(TBFu) 2 and PC 71 BM in twenty nine solvents. Commonly available laboratory solvents were chosen, as well as a number of solvents with similar Hansen parameters to chloroform, which is known to be a good solvent for this system, and several solvents with high dispersive parameters.…”

“…The absorption curves are reported in Figure S1 (Supporting Information) and the solubility results are reported in Table 1 . Chloroform ( CF ) is the best solvent for DPP(TBFu) 2 , which can dissolve up to 15.3 mg/mL followed by tetrabromoethane (8.25 mg/mL), thiophene ( Th ) and trichloroethylene, TCE , (7.21 mg/mL), and carbon disulfi de ( CS 2 ), tetrahydrofuran, and o -dichlorobenzene ( ∼ 4.40 mg/mL). For PC 71 BM , tetrabromoethane is the best solvent, which can dissolve over 480 mg/mL, followed by methylene iodide (357 mg/mL), o-dichlorobenzene ( ∼ 203 mg/mL), trichloroethylene (160 mg/mL), carbon disulfi de (142 mg/mL), and o -xylene, chloroform, and chlorobenzene ( ∼ 61 mg/mL).…”

“…Our group has recently explored a class of small-molecule donor compounds based on the diketopyrrolopyrrole chromophore unit. [13][14][15][16] We have observed power conversion effi ciencies (PCEs) of up to 4.4% using 3,6-bis(5-(benzofuran-2-yl)thiophen-2-yl)-2,5-bis(2-ethylhexyl)pyrrolo [3,4-c]pyrrole-1,4-dione DPP(TBFu) 2 as a donor, [ 17 ] which ranks among most effi cient BHJ systems known to date for small molecular donors. The high effi ciencies we observed with the DPP donors are in contrast to a signifi cant amount of work which has been done with other small-molecule donor materials.…”

“…In this contribution, we explore CEDs and Hansen parameters as tools to help understand the process of BHJ formation and as an aid in the selection and design of donor-acceptorsolvent systems to achieve effective solar cells. Atomic force microscopy (AFM) and photoconducting AFM (pc-AFM) were used to examine surface morphology of as-cast and annealed DPP(TBFu) 2 : PC 71 BM fi lms spun from different solvents. Device performance was evaluated and correlated to fi lm morphology and solvent parameters.…”