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Tian et al. Soft Sci 2023;3:30 https://dx.doi.org/10.20517/ss.2023.21 Page 13 of 27

Table 2. Summary of typical flexible e-skin sensors and comparison of their sensing performance

Authors Mechanism Stimuli Sensitivity Main materials Structure Fabrication
[11]
Wang et al. PR-TE P-T P: 0.0918 /kPa PANI, CNT, PDMS 3D porous structure Freeze-drying
T: 17.1 µV/K
[13]
Li et al. PR-TE S-T S: 220.8 (0-5%), MXene, AgNW, “Brick and mortar” Screen printing
1933.3 (53%-62%) PEDOT:PSS, TeNW structure
T: 0.2 ℃
(resolution)
[14]
Jung et al. PR-TE P-T - PEDOT: PSS, AgNP, Micro-pyramid Paper-based inkjet
MWCNT, PDMS structure printing
[15]
Zhang et al. PR-TE P-T P: 28.9 /kPa PEDOT:PSS, PU Porous structure Chemical vapor
T: < 0.1 K deposition
(resolution)
[23]
Rao et al. TrE-TR P-T P: 5.07 mV/Pa BiTO NP, rGO, PDMS Micro-pyramid Coating
T: 0.015 /℃ structure and
multilayers
You et al. [24] PC-TR S-T - EMIMTFSI, AgNW, SEBS Multilayers Spin-coating
[27]
Zhang et al. PR-TE S-P-T P: - SWCNT, ZnO, PVDF Barrel multilayer Electrostatic spinning
T: 0.025 /℃ structure
[71]
Shin et al. PE-TR P-T P: - Li, ZnO, PDMS, AgNW, Multilayers Spray-coating, spin-
T: 0.0052 /℃ PEDOT: PSS coating
Gao et al. [72] PC-TR P-T P: 0.75 /kPa PU, MWCNT, XNB Multilayers Lamination process
(below 2 kPa)
0.0549 /kPa (above
2 kPa)
T: 0.00284 /℃
[73]
An et al. PC-TR P-T P: 0.00178 /kPa AgNF-AgNW, PEDOT: PSS, Multipixel Electrospinning and
(below 350 kPa) IGZO electrospraying
0.0000965 /kPa
(above 350 kPa)
T: -
Kim et al. [77] PC-TR S-P-T P: 0.86 /kPa MWCNT, PDMS Foam Self-assembling
T: -
[74]
Wang et al. PR-TR P-T P: 1185.8 /kPa PDMS, AgNP, PEDOT:PSS Nanofibers Electrospinning and
T: - coating
[75]
Kim et al. PR-TR P-T P: 2 /kPa PEDOT:PSS, PUD, AgNW Micro-pyramid Inkjet printing
T: 0.0032 /℃ structure
Song et al. [78] PE-PyE P-T P: 0.044 V/kPa BaTiO , Ag, PDMS Sandwich layer Coating
3
T: 0.048 V/℃
Lei et al. [79] Capacitive P-T P: 0.45 /kPa PDMA/NaCl/SDS Sandwich layer 3D printing
T: - hydrogels
Cao et al. [80] Frequency S-T S: 0.699 Graphene, SiO , Silicon Patterned films Redox process
2
T: 58.4 Hz/K rubber
PR-TE: piezoresistive and thermoelectric; TrE-TR: triboelectric and thermoresistive; PE-TR: piezoelectric and thermoresistive; PC-TR: piezo-
capacitive and thermoresistive; PR-TR: piezoresistive and thermoresistive; PE-PyE: piezoelectric and pyroelectric; P: pressure; T: temperature; S:
strain.

Different olectric output signals
In essence, the different electric output signals (DEOS) system can realize simultaneous pressure and
temperature sensing on account of distinguishable output, which intrinsically determines two charming
strengths. One is to avoid the design of complex back-end decoupling circuits to separate pressure and
temperature signals. The other is to dramatically reduce crosstalk between pressure and temperature signals
at the device level. Mostly, three combinations, including piezoresistive and thermoelectric sensors,
piezoelectric/triboelectric and thermoresistive sensors, and piezo-capacitive and thermoresistive sensors, are
discussed. Furthermore, we list recent studies on the above three mechanism combinations and summarize
them in respect of structural design.