N,N′-Di(1-naphthyl)-N,N′-diphenyl-(1,1′-biphenyl)-4,4′-diamine, also known as NPB or NPD, has been used intensively in OLEDs and other organic electronic devices such as polymer photovoltaics (OPV) and perovskite solar cells for its outstanding hole transport capability.

NPB is considered as one of the best materials within its competition, and has become the most common-used material in OLEDs' application. This is due to its increased Tg up to 95 °C, which enhances device morphology and is beneficial for device longevity [1].

General Information

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CAS number	123847-85-8
Chemical formula	C44H32N2
Molecular weight	588.74 g/mol
HOMO/LUMO	HOMO = 5.5 eV, LUMO = 2.4 eV
Absorption*	λmax 339 nm
Fluorescence	λem 450 nm (in THF)
Synonyms	NPB, NPD N,N′-Di(1-naphthyl)-N,N′-diphenyl-(1,1′-biphenyl)-4,4′-diamine N,N′-Bis(naphthalen-1-yl)-N,N′-bis(phenyl)benzidine
Classification / Family	Triphenylamines, Naphtalene, Hole-transport layer materials, Electron block layer materials, Hole-injection layer materials, Organic light-emitting diodes (OLEDs), OFETs, Organic Photovoltaics, Polymer solar cells, Perovskite solar cells

* Measurable with an USB spectrometer, see our spectrometer application notes.

Product Details

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Purity	> 99.5% (sublimed) > 98.0% (unsublimed)
Melting point	279-283 °C (lit.)
Appearance	Off-White powder

* Sublimation is a technique used to obtain ultra pure-grade chemicals, see sublimed materials.

Chemical Structure

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Chemical structure of N,N′-Di(1-naphthyl)-N,N′-diphenyl-(1,1′-biphenyl)-4,4′-diamine (NPB)

Device Structure(s)

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Device structure	ITO/NPB (30 nm)/NPB: DCJTB: C545T* (10 nm)/NPB (4 nm)/DNA (8 nm)/(BCP) (9 nm)/Alq3 (30 nm)/LiF (1 nm)/Al (100 nm) [2]
Colour	White
Max. Luminance	13,600 cd/m2
Max. Current Efficiency	12.3 cd/A
Max. Power Efficiency	4.4 lm W−1

Device structure	ITO/MoO3 (7nm)/NPB (85 nm)/ (PPQ)2Ir(acac):Ir(ppy)3:FIrpic:mCP/TAZ/LiF/Al [3]
Colour	White
Max. EQE	20.1%
Max. Power Efficiency	41.3 lm W−1

Device structure	ITO/PEDOT:PSS/NPB/mCP/FPt*(1.5 nm)/OXD-7/CsF/Al [4]
Colour	White
Max. EQE	17.5%
Max. Power Efficiency	45 lm W−1

Device structure	ITO/2-TNATA:33% WO3 (100 nm)/NPB (10 nm)/Alq3 (30 nm)/Bphen (20 nm)/BPhen: 2% Cs (10 nm)/Al (150 nm) [5]
Colour	Green
Operating Voltage for 100 cd/m2	3.1 V
Current Efficiency for 20 mA/cm2	4.4 cd/A
Power Efficiency for 20 mA/cm2	3.3 lm W−1

Device structure	ITO/2-TNATA (60 nm)/NPB (15 nm)/TAT* (30 nm)/ Alq3 (30 nm)/LiF (1 nm)/Al (200 nm) [6]
Colour	Deep Blue
EQE at 10 mA/cm2	7.18
Current Efficiency at 10 mA/cm2	3.64 cd/A
Power Efficiency at 10 mA/cm2	1.87 lm W−1

Device structure	ITO/[F4-TCNQ(x nm)/m-MTDATA(y nm)]n/NPB/Alq3/Bphen/Cs2CO3/Al [7]
Colour	Green
Max. Luminance	23,500 cd/m2
Max. Current Efficiency	7.0 cd/A
Max. Power Efficiency	4.46 lm W−1

Device structure	ITO/NPB (30 nm)/CBP:8 wt% (t-bt)2Ir(acac)* (15 nm)/ BPhen(35 nm)/LiF (1 nm)/CoPc:C60 (4:1) (5 nm)/ MoO3 (5 nm)/NPB(30 nm)/CBP:8 wt% (t-bt)2Ir(acac)* (15 nm)/ BPhen (35 nm)/Mg:Ag (100 nm) [8]
Colour	Yellow
Max. EQE	16.78%
Max. Luminance	42,236 cd/m2
Max. Current Efficiency	50.2 cd/A
Max. Power Efficiency	12.9 lm W−1

Device structure	ITO/NPB (60 nm)/BNA:2 wt% perylene and 0.5 wt% DCJTB* (35 nm)/Alq3 (25 nm)/Mg:Ag (200 nm) [9]
Colour	White
Max. Luminance	4,100 cd/m2
Max. Current Efficiency	1.65 cd/A

Device structure	ITO (100 nm)/NPB (40 nm)/ADN:C6:DCJTB (30 nm)/Alq (30 nm)/LiF (1 nm)/Al (100 nm)
Colour	Red
Max. Luminance	13, 000 cd/m2 [10]
Max. Current Efficiency	4.9 cd/A

*For chemical structure information please refer to the cited references.

Characterisation

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1H NMR of N,N′-Di(1-naphthyl)-N,N′-diphenyl-(1,1′-biphenyl)-4,4′-diamine (NPB) in CDCl3HPLC trace of N,N′-Di(1-naphthyl)-N,N′-diphenyl-(1,1′-biphenyl)-4,4′-diamine (NPB)