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In this communication, we report a typical structural, optical and electrical analysis of thin films of hole transport material (HTM) based on aromatic phenyl benzidine derivative (N,N${}^{\prime }$-Di-1-naphthyl-N,N${}^{\prime }$-diphenylbenzidine) deposited by thermal evaporation technique onto the glass substrate. The effect of substrate temperature on the physical and electronic properties of these organic thin films for perovskite solar cells (PSCs) applications has been investigated. The films have been characterized by FTIR, XRD, SEM, UV–Vis spectroscopy and photoluminescence spectroscopy. Electrical conductivity and activation energies of films have also been calculated. From FTIR data of fabricated films and powder, it was found that the compound does not decompose during the thermal evaporation process as observed vibrational frequencies of films and the powder are the same. From the results, it has been determined that the substrate temperature has a huge impact on the physical structure and has also influenced the optical, electrical properties of the films. As observed from the studies it appears that these amorphous films with bandgap near to 3eV and suitable conductivity have potential for photovoltaics layer devices. From this study, it can be concluded that N,N${}^{\prime }$-Di-1-naphthyl-N,N${}^{\prime }$-diphenylbenzidine can be used as an active hole transport layer in PSCs.

A fine balance between weak molecule-molecule interactions and usually only weakly laterally varying molecule-substrate interactions governs the physical structure of organic-inorganic and organic-organic heteroepitaxial thin films. Therefore, it is important to investigate the energetics of realistically large overlayer domains. So far, Potential calculations for large domains of organic overlayers on crystalline substrates were computationally demanding due to the vast number of atoms to be considered. Here, we present a technique which for the first time enables the calculation of both the molecule-substrate interaction potential and the molecule-molecule interaction potential for large molecular domains (up to several thousands of rather large molecules) by utilizing potential energy grid files. This technique does not only allow the investigation of the substrate influence but also full Monte-Carlo based structural optimizations, if applied to 2D crystalline overlayers. Furthermore, it provides an estimate for the energetic gain combined with the differently aligned overlayer domains. In several examples we will discuss the usefulness of this method. As a general result, we will provide evidence that energetically favorable lattice structures in OMBE systems are not restricted to commensurate unit cells or coincident super cells.

The organic thin films of stearic acid/pyrazoline nanoparticles were prepared by transferring Langmuir monolayer of stearic acid/pyrazoline nanoparticle onto the solid substrate. The complex of stearic acid/pyrazoline nanoparticle was studied with pressure–area isotherm at the air/water interface and identified with linearly increasing optical absorbance around 370 nm by increasing the number of deposited layers. The in situ domain structure and molecular orientation of the complex were measured with BAM. The surface morphology of the Langmuir–Blodgett film was observed with AFM. The dispersion of pyrazoline nanoparticle in the film was studied with TEM.

The following sections are included:

• Introduction

• UV Photoelectron Spectroscopy (UPS)
  • Methodology
    • General and Experimental Aspects
    • Theoretical Analysis of UPS Spectra
    • Energy Band Mapping for One-Dimensional Systems
  • Electronic Structure of Molecular Solids
    • Density of States, Solid State Effect, and Angular Dependence
    • The Use of the Tunability of Synchrotron Radiation
    • Intermolecular Energy Band Mapping
  • Polymers and Oligomers
    • Density of States
    • Band Evolution in Oligomers
    • Intramolecular Energy Band Mapping
  • Electronic Structure of Binary Systems
    • Complexes
    • Interfaces
  • ARUPS as a Novel Probe of Molecular Orientation

• NEXAFS Spectroscopy
  • General and Experimental Aspects
  • Characteristics of Core Excitations
    • Selection Rules
    • Core Excitonic Effect
    • Spectral Assignments
    • Theoretical Simulation and Analysis
  • Molecular Orientation and Chemical States of π-Conjugated Systems
    • Molecules on Well Defined Surfaces
    • Other Studies of Molecules and Polymers in Various States
  • Electronic Structures of the Unoccupied States of π-Conjugated Systems
    • Aromatic Molecules
    • Fullerenes and Nanotube
    • Metal Complexes
    • π-Conjugated Polymers
    • Doping and Reactions
  • Alkanes and Compounds with Long Alkyl Chains
    • C K edge Absorption of Alkyl Chain
    • Compounds with Long Alkyl Chains
  • Other Polymers and Their Surfaces
    • Polymers with Fluorinated Chains
    • Silicon-Backboned Polymers
    • Polyimides and Their Rubbed States
    • Other Polymers
  • Other Applications

• Acknowledgments

• References