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Tian et al. Soft Sci 2023;3:30 https://dx.doi.org/10.20517/ss.2023.21 Page 15 of 27

Figure 6. Typical piezoresistive and thermoelectric sensors. (A) Printable and stretchable temperature-strain dual-sensing
nanocomposite with high sensitivity and perfect stimulus discriminability. Reproduced with permission [13] . Copyright 2020, American
Chemical Society. (B) Paper-based bimodal sensor for electronic skin applications. Reproduced with permission [14] . Copyright 2017,
American Chemical Society. (C) Flexible and self-powered temperature-pressure dual-parameter sensors using microstructure-frame-
supported organic thermoelectric materials. Reproduced with permission [15] . Copyright 2015, Springer Nature.

Same electric output signals
As previously stated, a DEOS system avoids the crosstalk and decoupling process between pressure and
temperature signals. However, it is inevitable for the same electric output signals (SEOS) system to generate
interference as a result of two same integrated mechanisms, which need signal decoupling and delicate
circuit design. Interestingly, electric signal exhibits positive and negative gradient in response to the same
trend of pressure and temperature stimuli. Given that, resistive-based pressure and temperature sensors are
widely studied and fabricated due to easy readout and relatively intuitive distinguishability. Besides,
[79]
[78]
conjuncted pyro-piezoelectric , capacitive , and frequency response-based sensors are introduced
[80]
briefly in this section.
For simultaneous pressure and temperature detection, a resistive mechanism can be utilized. For instance,
Wang et al. developed a flexible and multifunctional resistive sensor integrating uniform conductive coating
PEDOT: PSS and AgNP layers with an interlaced nanofibrous structure through a large-scale and cost-
efficient strategy . Due to structural design, the multilevel sensing paths comprising both interlaminar and
[74]
intrastratal signal transmissions fulfill the simultaneous and precise detection of pressure-temperature
stimuli without interference, as seen in Figure 9A. Kim et al. made a micro-pyramid patterned PEDOT:
PSS/AgNPs/PU film along with dogbone-shaped PEDOT: PSS/AgNPs/PI film by inkjet printing to
[75]
implement pressure and temperature distinguishable detecting , which could show the opposite resistance
change with different temperature trends, as illustrated in Figure 9B.