▁with ▁imp ur ities ▁from ▁the ▁solution . ▁Anne aling ▁is ▁required ▁to ▁improve ▁cry st all inity . ▁For ▁effic ien cies ▁higher ▁than ▁ 7 %, ▁a ▁sto ichi ometry ▁correction ▁are ▁required . ▁The ▁correction ▁was ▁originally ▁done ▁via ▁high ▁temperature ▁physical ▁v apor ▁de position , ▁which ▁is ▁not ▁practical ▁in ▁industry . ▁ <0x09> ▁Sol op ower ▁is ▁currently ▁producing ▁cells ▁with ▁> 1 3 . 7 % ▁conversion ▁efficiency ▁as ▁per ▁N RE L . ▁ ▁P rec ursor ▁combination ▁by ▁wa fer - b ond ing ▁inspired ▁technique ▁▁ ▁In ▁this ▁process , ▁two ▁different ▁prec ursor ▁films ▁are ▁depos ited ▁separately ▁on ▁a ▁substr ate ▁and ▁a ▁super str ate . ▁The ▁films ▁are ▁pressed ▁together ▁and ▁he ated ▁to ▁release ▁the ▁film ▁from ▁the ▁re usable ▁super str ate , ▁leaving ▁a ▁C IG S ▁absor ber ▁on ▁the ▁substr ate ▁( Fig ure ▁ 5 ). ▁H eli ov olt ▁pat ented ▁this ▁procedure ▁and ▁named ▁it ▁the ▁F AS ST ▁process . ▁In ▁principle , ▁the ▁prec urs ors ▁can ▁be ▁depos ited ▁at ▁low ▁temperature ▁using ▁low - cost ▁de position ▁techniques , ▁lower ing ▁module ▁cost . ▁However , ▁the ▁first ▁gener ations ▁of ▁products ▁use ▁higher ▁temperature ▁P VD ▁methods ▁and ▁do ▁not ▁achieve ▁full ▁cost ▁cutting ▁potential . ▁F lex ible ▁substr ates ▁could ▁eventually ▁be ▁used ▁in ▁this ▁process . ▁▁ <0x09> ▁Typ ical ▁film ▁characteristics ▁are ▁not ▁known ▁outside ▁of ▁the ▁company , ▁as ▁no ▁research