Investigation of structural and optoelectronic properties of annealed nickel phthalocyanine thin films

AuthorsMina Neghabi , Mehdi Zadsar,Seyed Mohammad Bagher Ghorashi
JournalMaterialsScienceinSemiconductorProcessing
Page number13–20
Paper TypeFull Paper
Published At4September2013
Journal GradeISI
Journal TypeTypographic
Journal CountryIran, Islamic Republic Of

Abstract

Thinfilmsofnickelphthalocyanine(NiPc)werepreparedbythermalevaporationandthe
effectsofannealingtemperatureonthestructuralandopticalpropertiesofthesamples
werestudiedusingdifferentanalyticalmethods.Structuralanalysisshowedthatthegrain
sizeandcrystallinityofNiPcfilmsimprovedasannealingtemperatureincreasedfrom25to
150 1C. Also,maximumgrainsize(71.3nm)wasobtainedat150 1C annealingtemperature.
In addition,NiPcfilmsannealedat150 1C hadaverysmoothsurfacewithanRMSroughness
of 0.41nm.Opticalanalysisindicatedthatbandgapenergyoffilmsatdifferentannealing
temperaturesvariedintherangeof3.22–3.28eV.Schottkydiodesolarcellswithastructure
of ITO/PEDOT:PSS/NiPc/Alwerefabricated.Measurementofthedarkcurrentdensity–
voltage(J–V) characteristicsofdiodesshowedthatthecurrentdensityoffilmsannealedat
150 1C foragivenbiaswasgreaterthanthatofotherfilms.Furthermore,thefilmsrevealed
thehighestrectificationratio(23.1)andlowestbarrierheight(0.84eV)demonstrating,
respectively,23%and11%increasecomparedwiththoseofthedepositedNiPcfilms.
Meanwhile,photoconversionbehavioroffilmsannealedat150 1C underillumination
showedthehighestshortcircuitcurrentdensity(0.070mA/cm2) andopencircuitvoltage
of (0.55V).